init

.idea/.gitignore

@@ -0,0 +1,10 @@
+# 默认忽略的文件
+/shelf/
+/workspace.xml
+# 已忽略包含查询文件的默认文件夹
+/queries/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
+# 基于编辑器的 HTTP 客户端请求
+/httpRequests/

.idea/100 Exercises to Learn Rust.iml

@@ -0,0 +1,302 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="EMPTY_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/BranchingIfElse/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/BranchingIfElse/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/BranchingIfElse/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/ConversionsAsCasting/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/ConversionsAsCasting/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/ConversionsAsCasting/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Factorial/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Factorial/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Factorial/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Integers/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Integers/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Integers/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Introduction/ABasicCalculatorIntroduction/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Introduction/ABasicCalculatorIntroduction/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/LoopsFor/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/LoopsFor/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/LoopsFor/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/LoopsWhile/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/LoopsWhile/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/LoopsWhile/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/OverflowAndUnderflow/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/OverflowAndUnderflow/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/OverflowAndUnderflow/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Panics/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Panics/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Panics/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/SaturatingArithmetic/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/SaturatingArithmetic/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/SaturatingArithmetic/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Variables/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Variables/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/ABasicCalculator/Variables/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/AsyncAwarePrimitives/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/AsyncAwarePrimitives/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/AsyncAwarePrimitives/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/AsynchronousFunctions/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/AsynchronousFunctions/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/AsynchronousFunctions/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/BlockingTheRuntime/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/BlockingTheRuntime/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/BlockingTheRuntime/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Cancellation/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Cancellation/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Cancellation/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/FutureTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/FutureTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/FutureTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Introduction/Futures - Introduction/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Introduction/Futures - Introduction/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Outro/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Outro/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Outro/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Runtime/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Runtime/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/Runtime/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/SpawningTasks/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/SpawningTasks/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Futures/SpawningTasks/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/GoingFurther/Epilogue/What next/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Introduction/GettingStarted/About/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Introduction/GettingStarted/CourseView/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Introduction/GettingStarted/Editor/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Introduction/GettingStarted/ExternalLinter/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Introduction/GettingStarted/HelloWorld/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Introduction/GettingStarted/HelloWorld/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Introduction/GettingStarted/NavigatingAround/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Introduction/GettingStarted/TaskDescription/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/AckPattern/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/AckPattern/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/AckPattern/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/BoundedChannels/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/BoundedChannels/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/BoundedChannels/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Channels/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Channels/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Channels/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Client/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Client/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Client/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/InteriorMutability/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/InteriorMutability/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/InteriorMutability/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Introduction/Threads - Introduction/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Introduction/Threads - Introduction/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/LeakingMemory/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/LeakingMemory/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/LeakingMemory/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/MutexSendAndArc/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/MutexSendAndArc/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/MutexSendAndArc/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Patching/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Patching/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Patching/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/RwLock/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/RwLock/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/RwLock/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/ScopedThreads/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/ScopedThreads/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/ScopedThreads/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/StaticLifetime/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/StaticLifetime/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/StaticLifetime/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/SyncTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/SyncTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/SyncTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Threads/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Threads/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/Threads/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/WithoutChannels/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/WithoutChannels/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Threads/WithoutChannels/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Arrays/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Arrays/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Arrays/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/BTreeMap/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/BTreeMap/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/BTreeMap/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Combinators/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Combinators/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Combinators/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/HashMap/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/HashMap/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/HashMap/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/ImplTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/ImplTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/ImplTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/ImplTraitPt2/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/ImplTraitPt2/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/ImplTraitPt2/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/IndexMutTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/IndexMutTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/IndexMutTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/IndexTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/IndexTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/IndexTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Introduction/Ticket Management - Introduction/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Introduction/Ticket Management - Introduction/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Iter/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Iter/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Iter/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Iterators/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Iterators/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Iterators/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Lifetimes/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Lifetimes/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Lifetimes/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/MutableSlices/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/MutableSlices/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/MutableSlices/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Resizing/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Resizing/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Resizing/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Slices/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Slices/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Slices/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/TwoStates/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/TwoStates/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/TwoStates/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Vectors/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Vectors/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketManagement/Vectors/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Destructors/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Destructors/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Destructors/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Encapsulation/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Encapsulation/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Encapsulation/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Heap/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Heap/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Heap/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Introduction/Ticket v1 - Introduction/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Introduction/Ticket v1 - Introduction/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Modules/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Modules/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Modules/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Outro/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Outro/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Outro/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Ownership/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Ownership/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Ownership/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/ReferencesInMemory/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/ReferencesInMemory/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/ReferencesInMemory/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Setters/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Setters/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Setters/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Stack/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Stack/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Stack/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Structs/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Structs/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Structs/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Validation/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Validation/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Validation/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Visibility/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Visibility/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV1/Visibility/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/BranchingIfLetAndLetElse/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/BranchingIfLetAndLetElse/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/BranchingIfLetAndLetElse/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/BranchingMatch/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/BranchingMatch/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/BranchingMatch/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Dependencies/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Dependencies/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Dependencies/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Enums/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Enums/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Enums/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorEnums/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorEnums/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorEnums/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorSource/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorSource/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorSource/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/ErrorTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Fallibility/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Fallibility/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Fallibility/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Introduction/Ticket v2 - Introduction/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Introduction/Ticket v2 - Introduction/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Nullability/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Nullability/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Nullability/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Outro/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Outro/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Outro/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Packages/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Packages/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Packages/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/TryFromTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/TryFromTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/TryFromTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Unwrap/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Unwrap/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/Unwrap/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/VariantsWithData/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/VariantsWithData/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/VariantsWithData/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/thiserror/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/thiserror/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/TicketV2/thiserror/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/AssociatedVsGenericTypes/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/AssociatedVsGenericTypes/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/AssociatedVsGenericTypes/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/CloneTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/CloneTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/CloneTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/CopyTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/CopyTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/CopyTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DerefTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DerefTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DerefTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DeriveMacros/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DeriveMacros/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DeriveMacros/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DropTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DropTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/DropTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/FromTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/FromTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/FromTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/Introduction/Traits - Introduction/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/Introduction/Traits - Introduction/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/OperatorOverloading/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/OperatorOverloading/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/OperatorOverloading/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/OrphanRule/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/OrphanRule/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/OrphanRule/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/Outro/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/Outro/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/Outro/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/SizedTrait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/SizedTrait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/SizedTrait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/StringSlices/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/StringSlices/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/StringSlices/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/Trait/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/Trait/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/Trait/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/TraitBounds/Task/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/TraitBounds/Task/tests" isTestSource="true" />
+      <sourceFolder url="file://$MODULE_DIR$/Traits/TraitBounds/Theory/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/helpers/common/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/helpers/ticket_fields/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/externalDependencies.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalDependencies">
+    <plugin id="com.jetbrains.rust" />
+    <plugin id="org.toml.lang" />
+  </component>
+</project>

.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/100 Exercises to Learn Rust.iml" filepath="$PROJECT_DIR$/.idea/100 Exercises to Learn Rust.iml" />
+    </modules>
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

ABasicCalculator/BranchingIfElse/Task/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "task_branching"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/BranchingIfElse/Task/src/lib.rs

@@ -0,0 +1,14 @@
+/// Return `12` if `n` is even,
+/// `13` if `n` is divisible by `3`,
+/// `17` otherwise.
+pub fn magic_number(n: u32) -> u32 {
+    if n % 2 == 0 {
+        12
+    }else {
+        if n % 3 == 0 {
+            13
+        }else {
+            17
+        }
+    }
+}

ABasicCalculator/BranchingIfElse/Task/task-info.yaml

@@ -0,0 +1,27 @@
+type: edu
+files:
+  - name: src/lib.rs
+    visible: true
+    placeholders:
+      - offset: 130
+        length: 124
+        placeholder_text: /*TODO*/
+        initial_state:
+          length: 8
+          offset: 130
+        initialized_from_dependency: false
+        encrypted_possible_answer: rU7BVkr6lh0wIe5YDtA/A+e3+1BNLrsCW2VgoPzfdPF5P2Ia2xJxNciLcRMq74me52Iw6Lw9hxW5PKwStenwlctnVW29NoM3m46gINTf69np4DKVU88oj56TzKcVvLao
+        selected: true
+        status: Solved
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+  - name: tests/tests.rs
+    visible: false
+    learner_created: false
+status: Solved
+feedback:
+  message: 恭喜!
+  time: "Tue, 24 Feb 2026 08:31:17 UTC"
+record: -1

ABasicCalculator/BranchingIfElse/Task/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 839362726

ABasicCalculator/BranchingIfElse/Task/task.md

@@ -0,0 +1,2 @@
+This task involves implementing the `magic_number` function.
+The `magic_number` function takes an unsigned `32-bit` integer `n` as input and should return a `u32` based on the rules in code comment.

ABasicCalculator/BranchingIfElse/Theory/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "theory_branching"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/BranchingIfElse/Theory/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    // put your code here to launch it
+}

ABasicCalculator/BranchingIfElse/Theory/task-info.yaml

@@ -0,0 +1,11 @@
+type: theory
+files:
+  - name: src/main.rs
+    visible: true
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+status: Solved
+record: -1
+post_submission_on_open: true

ABasicCalculator/BranchingIfElse/Theory/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 48107198

ABasicCalculator/BranchingIfElse/Theory/task.md

@@ -0,0 +1,133 @@
+## Control flow
+
+All our programs so far have been pretty straightforward.\
+A sequence of instructions is executed from top to bottom, and that's it.
+
+It's time to introduce some **branching**.
+
+## `if` clauses
+
+The `if` keyword is used to execute a block of code only if a condition is true.
+
+Here's a simple example:
+
+```rust
+let number = 3;
+if number < 5 {
+    println!("`number` is smaller than 5");
+}
+```
+
+This program will print `number is smaller than 5` because the condition `number < 5` is true.
+
+### `else` clauses
+
+Like most programming languages, Rust supports an optional `else` branch to execute a block of code when the condition in an
+`if` expression is false.\
+For example:
+
+```rust
+let number = 3;
+
+if number < 5 {
+    println!("`number` is smaller than 5");
+} else {
+    println!("`number` is greater than or equal to 5");
+}
+```
+
+### `else if` clauses
+
+Your code drifts more and more to the right when you have multiple `if` expressions, one nested inside the other.
+
+```rust
+let number = 3;
+
+if number < 5 {
+    println!("`number` is smaller than 5");
+} else {
+    if number >= 3 {
+        println!("`number` is greater than or equal to 3, but smaller than 5");
+    } else {
+        println!("`number` is smaller than 3");
+    }
+}
+```
+
+You can use the `else if` keyword to combine multiple `if` expressions into a single one:
+
+```rust
+let number = 3;
+
+if number < 5 {
+    println!("`number` is smaller than 5");
+} else if number >= 3 {
+    println!("`number` is greater than or equal to 3, but smaller than 5");
+} else {
+    println!("`number` is smaller than 3");
+}
+```
+
+## Booleans
+
+The condition in an `if` expression must be of type `bool`, a **boolean**.\
+Booleans, just like integers, are a primitive type in Rust.
+
+A boolean can have one of two values: `true` or `false`.
+
+### No truthy or falsy values
+
+If the condition in an `if` expression is not a boolean, you'll get a compilation error.
+
+For example, the following code will not compile:
+
+```rust
+let number = 3;
+if number {
+    println!("`number` is not zero");
+}
+```
+
+You'll get the following compilation error:
+
+```text
+error[E0308]: mismatched types
+ --> src/main.rs:3:8
+  |
+3 |     if number {
+  |        ^^^^^^ expected `bool`, found integer
+```
+
+This follows from Rust's philosophy around type coercion: there's no automatic conversion from non-boolean types to booleans.
+Rust doesn't have the concept of **truthy** or **falsy** values, like JavaScript or Python.\
+You have to be explicit about the condition you want to check.
+
+### Comparison operators
+
+It's quite common to use comparison operators to build conditions for `if` expressions.\
+Here are the comparison operators available in Rust when working with integers:
+
+- `==`: equal to
+- `!=`: not equal to
+- `<`: less than
+- `>`: greater than
+- `<=`: less than or equal to
+- `>=`: greater than or equal to
+
+## `if/else` is an expression
+
+In Rust, `if` expressions are **expressions**, not statements: they return a value.\
+That value can be assigned to a variable or used in other expressions. For example:
+
+```rust
+let number = 3;
+let message = if number < 5 {
+    "smaller than 5"
+} else {
+    "greater than or equal to 5"
+};
+```
+
+In the example above, each branch of the `if` evaluates to a string literal,
+which is then assigned to the `message` variable.\
+The only requirement is that both `if` branches return the same type.

ABasicCalculator/BranchingIfElse/lesson-info.yaml

@@ -0,0 +1,4 @@
+custom_name: Branching if-else
+content:
+  - Theory
+  - Task

ABasicCalculator/BranchingIfElse/lesson-remote-info.yaml

@@ -0,0 +1 @@
+id: 822833509

ABasicCalculator/ConversionsAsCasting/Task/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "task_conversions_as_casting"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/ConversionsAsCasting/Task/src/lib.rs

@@ -0,0 +1 @@
+

ABasicCalculator/ConversionsAsCasting/Task/task-info.yaml

@@ -0,0 +1,44 @@
+type: edu
+files:
+  - name: src/lib.rs
+    visible: false
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+  - name: tests/tests.rs
+    visible: true
+    placeholders:
+      - offset: 81
+        length: 10
+        placeholder_text: /* TODO */
+        initial_state:
+          length: 10
+          offset: 81
+        initialized_from_dependency: false
+        encrypted_possible_answer: 4w33P5f+Ces/HqPWq0IorA==
+        selected: false
+        status: Unchecked
+      - offset: 920
+        length: 10
+        placeholder_text: /* TODO */
+        initial_state:
+          length: 10
+          offset: 920
+        initialized_from_dependency: false
+        encrypted_possible_answer: RESya3fqSV1DFqjsTgSSYQ==
+        selected: false
+        status: Unchecked
+      - offset: 1020
+        length: 10
+        placeholder_text: /* TODO */
+        initial_state:
+          length: 10
+          offset: 1020
+        initialized_from_dependency: false
+        encrypted_possible_answer: oa+nVSRiKi7L3SNrfCrSCA==
+        selected: false
+        status: Unchecked
+    learner_created: false
+status: Unchecked
+record: -1

ABasicCalculator/ConversionsAsCasting/Task/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 1735357693

ABasicCalculator/ConversionsAsCasting/Task/task.md

@@ -0,0 +1 @@
+This task is to replace TODOs in the tests with the correct values for explicit type conversions, applying Rust's casting rules.

ABasicCalculator/ConversionsAsCasting/Task/tests/tests.rs

@@ -0,0 +1,34 @@
+#[cfg(test)]
+mod tests {
+
+    #[test]
+    fn u16_to_u32() {
+        let v: u32 = /* TODO */;
+        assert_eq!(47u16 as u32, v);
+    }
+
+    #[test]
+    fn u8_to_i8() {
+        // The compiler is smart enough to know that the value 255 cannot fit
+        // inside an i8, so it'll emit a hard error. We intentionally disable
+        // this guardrail to make this (bad) conversion possible.
+        // The compiler is only able to pick on this because the value is a
+        // literal. If we were to use a variable, the compiler wouldn't be able to
+        // catch this at compile time.
+        #[allow(overflowing_literals)]
+        let x = { 255 as i8 };
+
+        // You could solve this by using exactly the same expression as above,
+        // but that would defeat the purpose of the exercise. Instead, use a genuine
+        // `i8` value that is equivalent to `255` when converted from `u8`.
+        let y: i8 = /* TODO */;
+
+        assert_eq!(x, y);
+    }
+
+    #[test]
+    fn bool_to_u8() {
+        let v: u8 = /* TODO */;
+        assert_eq!(true as u8, v);
+    }
+}

ABasicCalculator/ConversionsAsCasting/Theory/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "theory_conversions_as_casting"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/ConversionsAsCasting/Theory/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    // put your code here to launch it
+}

ABasicCalculator/ConversionsAsCasting/Theory/task-info.yaml

@@ -0,0 +1,11 @@
+type: theory
+files:
+  - name: src/main.rs
+    visible: true
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+status: Unchecked
+record: -1
+post_submission_on_open: true

ABasicCalculator/ConversionsAsCasting/Theory/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 1217457677

ABasicCalculator/ConversionsAsCasting/Theory/task.md

@@ -0,0 +1,102 @@
+## Conversions, `as` casting
+
+We've repeated over and over again that Rust won't perform
+implicit type conversions for integers.\
+How do you perform _explicit_ conversions then?
+
+## `as`
+
+You can use the `as` operator to convert between integer types.\
+`as` conversions are **infallible**.
+
+For example:
+
+```rust
+let a: u32 = 10;
+
+// Cast `a` into the `u64` type
+let b = a as u64;
+
+// You can use `_` as the target type
+// if it can be correctly inferred 
+// by the compiler. For example:
+let c: u64 = a as _;
+```
+
+The semantics of this conversion are what you expect: all `u32` values are valid `u64`
+values.
+
+### Truncation
+
+Things get more interesting if we go in the opposite direction:
+
+```rust
+// A number that's too big 
+// to fit into a `u8`
+let a: u16 = 255 + 1;
+let b = a as u8;
+```
+
+This program will run without issues, because `as` conversions are infallible.
+But what is the value of `b`?
+When going from a larger integer type to a smaller, the Rust compiler will perform
+a **truncation**.
+
+To understand what happens, let's start by looking at how `256u16` is
+represented in memory, as a sequence of bits:
+
+```text
+ 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0
+|               |               |
++---------------+---------------+
+  First 8 bits    Last 8 bits
+```
+
+When converting to a `u8`, the Rust compiler will keep the last 8 bits of a `u16`
+memory representation:
+
+```text
+ 0 0 0 0 0 0 0 0 
+|               |
++---------------+
+  Last 8 bits
+```
+
+Hence `256 as u8` is equal to `0`. That's... not ideal, in most scenarios.\
+In fact, the Rust compiler will actively try to stop you if it sees you trying
+to cast a literal value which will result in a truncation:
+
+```text
+error: literal out of range for `i8`
+  |
+4 |     let a = 255 as i8;
+  |             ^^^
+  |
+  = note: the literal `255` does not fit into the type `i8` 
+          whose range is `-128..=127`
+  = help: consider using the type `u8` instead
+  = note: `#[deny(overflowing_literals)]` on by default
+```
+
+### Recommendation
+
+As a rule of thumb, be quite careful with `as` casting.\
+Use it _exclusively_ for going from a smaller type to a larger type.
+To convert from a larger to smaller integer type, rely on the
+[_fallible_ conversion machinery](../../../Ticket%20v2/TryFrom%20trait/Theory/task.md) that we'll
+explore later in the course.
+
+### Limitations
+
+Surprising behaviour is not the only downside of `as` casting.
+It is also fairly limited: you can only rely on `as` casting
+for primitive types and a few other special cases.\
+When working with composite types, you'll have to rely on
+different conversion mechanisms ([fallible](../../../Ticket%20v2/TryFrom%20trait/Theory/task.md)
+and [infallible](../../../Traits/From%20trait/Theory/task.md), which we'll explore later on.
+
+## Further reading
+
+- Check out [Rust's official reference](https://doc.rust-lang.org/reference/expressions/operator-expr.html#numeric-cast)
+  to learn the precise behaviour of `as` casting for each source/target combination,
+  as well as the exhaustive list of allowed conversions.

ABasicCalculator/ConversionsAsCasting/lesson-info.yaml

@@ -0,0 +1,4 @@
+custom_name: Conversions - as casting
+content:
+  - Theory
+  - Task

ABasicCalculator/ConversionsAsCasting/lesson-remote-info.yaml

@@ -0,0 +1 @@
+id: 3739315

ABasicCalculator/Factorial/Task/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "task_factorial"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/Factorial/Task/src/lib.rs

@@ -0,0 +1,19 @@
+// Define a function named `factorial` that, given a non-negative integer `n`,
+// returns `n!`, the factorial of `n`.
+//
+// The factorial of `n` is defined as the product of all positive integers up to `n`.
+// For example, `5!` (read "five factorial") is `5 * 4 * 3 * 2 * 1`, which is `120`.
+// `0!` is defined to be `1`.
+//
+// We expect `factorial(0)` to return `1`, `factorial(1)` to return `1`,
+// `factorial(2)` to return `2`, and so on.
+//
+// Use only what you learned! No loops yet, so you'll have to use recursion!
+
+pub fn factorial(n: u32) -> u32 {
+    if n != 0 {
+        n * factorial(n - 1)
+    }else {
+        1
+    }
+}

ABasicCalculator/Factorial/Task/task-info.yaml

@@ -0,0 +1,27 @@
+type: edu
+files:
+  - name: src/lib.rs
+    visible: true
+    placeholders:
+      - offset: 523
+        length: 108
+        placeholder_text: /* TODO */
+        initial_state:
+          length: 10
+          offset: 523
+        initialized_from_dependency: false
+        encrypted_possible_answer: VcN7n8pN4juX6JH6PuAoIET4D3fNlzyc+WYl3i8r9MHkJ6iLk8VkX3L1do206H7+S6ZfqVHEv28mHnLz+wsPev/UUThmXE/wtS0Ip/cM9NGimnr3L5b7m4V9IVVtJlmVfNpuaGBBnsEQ+vZO/YVaqQ==
+        selected: true
+        status: Solved
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+  - name: tests/tests.rs
+    visible: false
+    learner_created: false
+status: Solved
+feedback:
+  message: 恭喜!
+  time: "Tue, 24 Feb 2026 08:50:18 UTC"
+record: -1

ABasicCalculator/Factorial/Task/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 2112961728

ABasicCalculator/Factorial/Task/task.md

@@ -0,0 +1,2 @@
+This task is to implement the `factorial` function. 
+As instructed by the comments in the code, you must calculate `n!` for a non-negative integer `n` using recursion, without using loops.

ABasicCalculator/Factorial/Theory/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "theory_factorial"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/Factorial/Theory/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    // put your code here to launch it
+}

ABasicCalculator/Factorial/Theory/task-info.yaml

@@ -0,0 +1,11 @@
+type: theory
+files:
+  - name: src/main.rs
+    visible: true
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+status: Solved
+record: -1
+post_submission_on_open: true

ABasicCalculator/Factorial/Theory/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 1963166623

ABasicCalculator/Factorial/Theory/task.md

@@ -0,0 +1,11 @@
+## Factorial
+##
+So far you've learned:
+
+- How to define a function
+- How to call a function
+- Which integer types are available in Rust
+- Which arithmetic operators are available for integers
+- How to execute conditional logic via comparisons and `if`/`else` expressions
+
+It looks like you're ready to tackle factorials!

ABasicCalculator/Factorial/lesson-info.yaml

@@ -0,0 +1,3 @@
+content:
+  - Theory
+  - Task

ABasicCalculator/Factorial/lesson-remote-info.yaml

@@ -0,0 +1 @@
+id: 1811428691

ABasicCalculator/Integers/Task/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "task_integers"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/Integers/Task/src/lib.rs

@@ -0,0 +1,5 @@
+pub fn compute(a: u32, b: u32) -> u32 {
+    // TODO: change the line below to fix the compiler error and make the tests pass.
+    let multiplier: u32 = 4;
+    a + b * multiplier
+}

ABasicCalculator/Integers/Task/task-info.yaml

@@ -0,0 +1,27 @@
+type: edu
+files:
+  - name: src/lib.rs
+    visible: true
+    placeholders:
+      - offset: 146
+        length: 3
+        placeholder_text: /*TODO*/
+        initial_state:
+          length: 8
+          offset: 146
+        initialized_from_dependency: false
+        encrypted_possible_answer: tW4+HiJ7rgGNCq5MZ0RUQQ==
+        selected: false
+        status: Solved
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+  - name: tests/tests.rs
+    visible: false
+    learner_created: false
+status: Solved
+feedback:
+  message: 恭喜!
+  time: "Tue, 24 Feb 2026 07:19:08 UTC"
+record: -1

ABasicCalculator/Integers/Task/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 829886820

ABasicCalculator/Integers/Task/task.md

@@ -0,0 +1,2 @@
+This task is to modify the `compute` function to resolve a compiler error and allow tests to pass.
+Check `TODO` comment in the code.

ABasicCalculator/Integers/Theory/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "theory_integers"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/Integers/Theory/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    // put your code here to launch it
+}

ABasicCalculator/Integers/Theory/task-info.yaml

@@ -0,0 +1,11 @@
+type: theory
+files:
+  - name: src/main.rs
+    visible: true
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+status: Solved
+record: -1
+post_submission_on_open: true

ABasicCalculator/Integers/Theory/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 2019333427

ABasicCalculator/Integers/Theory/task.md

@@ -0,0 +1,129 @@
+## Primitive types
+
+`u32` is one of Rust's **primitive types**. Primitive types are the most basic building blocks of a language.
+They're built into the language itself—i.e. they are not defined in terms of other types.
+
+You can combine these primitive types to create more complex types. We'll see how soon enough.
+
+## Integers
+
+`u32`, in particular, is an **unsigned 32-bit integer**.
+
+An integer is a number that can be written without a fractional component. E.g. `1` is an integer, while `1.2` is not.
+
+### Signed vs. unsigned
+
+An integer can be **signed** or **unsigned**.\
+An unsigned integer can only represent non-negative numbers (i.e. `0` or greater).
+A signed integer can represent both positive and negative numbers (e.g. `-1`, `12`, etc.).
+
+The `u` in `u32` stands for **unsigned**.\
+The equivalent type for signed integer is `i32`, where the `i` stands for integer (i.e. any integer, positive or
+negative).
+
+### Bit width
+
+The `32` in `u32` refers to the **number of bits[^bit]** used to represent the number in memory.\
+The more bits, the larger the range of numbers that can be represented.
+
+Rust supports multiple bit widths for integers: `8`, `16`, `32`, `64`, `128`.
+
+With 32 bits, `u32` can represent numbers from `0` to `2^32 - 1` (a.k.a. [`u32::MAX`](https://doc.rust-lang.org/std/primitive.u32.html#associatedconstant.MAX)).\
+With the same number of bits, a signed integer (`i32`) can represent numbers from `-2^31` to `2^31 - 1`
+(i.e. from [`i32::MIN`](https://doc.rust-lang.org/std/primitive.i32.html#associatedconstant.MIN)
+to [`i32::MAX`](https://doc.rust-lang.org/std/primitive.i32.html#associatedconstant.MAX)).\
+The maximum value for `i32` is smaller than the maximum value for `u32` because one bit is used to represent
+the sign of the number. Check out the [two's complement](https://en.wikipedia.org/wiki/Two%27s_complement)
+representation for more details on how signed integers are represented in memory.
+
+### Summary
+
+Combining the two variables (signed/unsigned and bit width), we get the following integer types:
+
+| Bit width | Signed | Unsigned |
+| --------- | ------ | -------- |
+| 8-bit     | `i8`   | `u8`     |
+| 16-bit    | `i16`  | `u16`    |
+| 32-bit    | `i32`  | `u32`    |
+| 64-bit    | `i64`  | `u64`    |
+| 128-bit   | `i128` | `u128`   |
+
+## Literals
+
+A **literal** is a notation for representing a fixed value in source code.\
+For example, `42` is a Rust literal for the number forty-two.
+
+### Type annotations for literals
+
+But all values in Rust have a type, so... what's the type of `42`?
+
+The Rust compiler will try to infer the type of a literal based on how it's used.\
+If you don't provide any context, the compiler will default to `i32` for integer literals.\
+If you want to use a different type, you can add the desired integer type as a suffix—e.g. `2u64` is a 2 that's
+explicitly typed as a `u64`.
+
+### Underscores in literals
+
+You can use underscores `_` to improve the readability of large numbers.\
+For example, `1_000_000` is the same as `1000000`.
+
+## Arithmetic operators
+
+Rust supports the following arithmetic operators[^traits] for integers:
+
+- `+` for addition
+- `-` for subtraction
+- `*` for multiplication
+- `/` for division
+- `%` for remainder
+
+Precedence and associativity rules for these operators are the same as in mathematics.\
+You can use parentheses to override the default precedence. E.g. `2 * (3 + 4)`.
+
+> ⚠️ **Warning**
+>
+> The division operator `/` performs integer division when used with integer types.
+> I.e. the result is truncated towards zero. For example, `5 / 2` is `2`, not `2.5`.
+
+## No automatic type coercion
+
+As we discussed in the previous exercise, Rust is a statically typed language.\
+In particular, Rust is quite strict about type coercion. It won't automatically convert a value from one type to
+another[^coercion],
+even if the conversion is lossless. You have to do it explicitly.
+
+For example, you can't assign a `u8` value to a variable with type `u32`, even though all `u8` values are valid `u32`
+values:
+
+```rust
+let b: u8 = 100;
+let a: u32 = b;
+```
+
+It'll throw a compilation error:
+
+```text
+error[E0308]: mismatched types
+  |
+3 |     let a: u32 = b;
+  |            ---   ^ expected `u32`, found `u8`
+  |            |
+  |            expected due to this
+  |
+```
+
+We'll see how to convert between types [later in this course](../../../Traits/From%20trait/Theory/task.md)
+
+## Further reading
+
+- [The integer types section](https://doc.rust-lang.org/book/ch03-02-data-types.html#integer-types) in the official Rust book
+
+[^bit]: A bit is the smallest unit of data in a computer. It can only have two values: `0` or `1`.
+
+[^traits]: Rust doesn't let you define custom operators, but it puts you in control of how the built-in operators
+behave.
+We'll talk about operator overloading [later in the course](../../../Traits/Operator%20overloading/Theory/task.md), after we've covered traits.
+
+[^coercion]: There are some exceptions to this rule, mostly related to references, smart pointers and ergonomics. We'll
+cover those [later on](../../../Traits/Deref%20trait/Theory/task.md).
+A mental model of "all conversions are explicit" will serve you well in the meantime.

ABasicCalculator/Integers/lesson-info.yaml

@@ -0,0 +1,3 @@
+content:
+  - Theory
+  - Task

ABasicCalculator/Integers/lesson-remote-info.yaml

@@ -0,0 +1 @@
+id: 2091772948

ABasicCalculator/Introduction/ABasicCalculatorIntroduction/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "task_calculator_intro"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/Introduction/ABasicCalculatorIntroduction/src/lib.rs

@@ -0,0 +1,4 @@
+pub fn intro() -> &'static str {
+    // TODO: fix me 👇
+    "I'm ready to insert here missing part!"
+}

ABasicCalculator/Introduction/ABasicCalculatorIntroduction/task-info.yaml

@@ -0,0 +1,25 @@
+type: edu
+custom_name: A Basic Calculator - Introduction
+files:
+  - name: src/lib.rs
+    visible: true
+    placeholders:
+      - offset: 74
+        length: 24
+        placeholder_text: insert here missing part
+        initial_state:
+          length: 24
+          offset: 74
+        initialized_from_dependency: false
+        encrypted_possible_answer: p3YK31DNwkPk7JQv1wH1uCEizKYwTqJR03+cEeW8LH4=
+        selected: false
+        status: Unchecked
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+  - name: tests/tests.rs
+    visible: false
+    learner_created: false
+status: Unchecked
+record: -1

ABasicCalculator/Introduction/ABasicCalculatorIntroduction/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 940025367

ABasicCalculator/Introduction/ABasicCalculatorIntroduction/task.md

@@ -0,0 +1,22 @@
+# A Basic Calculator
+
+In this section we'll learn how to use Rust as a **calculator**.\
+It might not sound like much, but it'll give us a chance to cover a lot of Rust's basics, such as:
+
+- How to define and call functions
+- How to declare and use variables
+- Primitive types (integers and booleans)
+- Arithmetic operators (including overflow and underflow behavior)
+- Comparison operators
+- Control flow
+- Panics
+
+Nailing the basics with a few exercises will get the language flowing under your fingers.
+When we move on to more complex topics, such as traits and ownership, you'll be able to focus on the new concepts
+without getting bogged down by the syntax or other trivial details.
+
+<br/>
+
+## Task
+Introduction task is to complete the `intro` function. 
+The function should return the string: ***I'm ready to build a calculator in Rust!***

ABasicCalculator/Introduction/lesson-info.yaml

@@ -0,0 +1,2 @@
+content:
+  - ABasicCalculatorIntroduction

ABasicCalculator/Introduction/lesson-remote-info.yaml

@@ -0,0 +1 @@
+id: 888485854

ABasicCalculator/LoopsFor/Task/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "task_loops_for"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/LoopsFor/Task/src/lib.rs

@@ -0,0 +1,8 @@
+// Rewrite the factorial function using a `for` loop.
+pub fn factorial(n: u32) -> u32 {
+    let mut sum = 1;
+    for i in 1..=n {
+        sum *= i;
+    }
+    sum
+}

ABasicCalculator/LoopsFor/Task/task-info.yaml

@@ -0,0 +1,27 @@
+type: edu
+files:
+  - name: src/lib.rs
+    visible: true
+    placeholders:
+      - offset: 87
+        length: 74
+        placeholder_text: /* TODO */
+        initial_state:
+          length: 10
+          offset: 92
+        initialized_from_dependency: false
+        encrypted_possible_answer: E4RC0YxYtJ+r3XYct3/Vba0lSc2c1ujicbHBtaLiY6Dv+JMbZ+ZieR5jWv2O0Sq0e1xRAbtzWtjuylhM3Rln3MjtarbpC5noupVT80PyMn0=
+        selected: true
+        status: Solved
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+  - name: tests/tests.rs
+    visible: false
+    learner_created: false
+status: Solved
+feedback:
+  message: 恭喜!
+  time: "Tue, 24 Feb 2026 09:15:32 UTC"
+record: -1

ABasicCalculator/LoopsFor/Task/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 726352232

ABasicCalculator/LoopsFor/Task/task.md

@@ -0,0 +1 @@
+This task requires you to rewrite the `factorial` function using a `for` loop.

ABasicCalculator/LoopsFor/Theory/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "theory_loops_for"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/LoopsFor/Theory/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    // put your code here to launch it
+}

ABasicCalculator/LoopsFor/Theory/task-info.yaml

@@ -0,0 +1,11 @@
+type: theory
+files:
+  - name: src/main.rs
+    visible: true
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+status: Solved
+record: -1
+post_submission_on_open: true

ABasicCalculator/LoopsFor/Theory/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 900138695

ABasicCalculator/LoopsFor/Theory/task.md

@@ -0,0 +1,64 @@
+## Loops, part 2: `for`
+
+Having to manually increment a counter variable is somewhat tedious. The pattern is also extremely common!\
+To make this easier, Rust provides a more concise way to iterate over a range of values: the `for` loop.
+
+## The `for` loop
+
+A `for` loop is a way to execute a block of code for each element in an iterator[^iterator].
+
+Here's the general syntax:
+
+```rust
+for <element> in <iterator> {
+    // code to execute
+}
+```
+
+## Ranges
+
+Rust's standard library provides **range** type that can be used to iterate over a sequence of numbers[^weird-ranges].
+
+For example, if we want to sum the numbers from 1 to 5:
+
+```rust
+let mut sum = 0;
+for i in 1..=5 {
+    sum += i;
+}
+```
+
+Every time the loop runs, `i` will be assigned the next value in the range before executing the block of code.
+
+There are five kinds of ranges in Rust:
+
+- `1..5`: A (half-open) range. It includes all numbers from 1 to 4. It doesn't include the last value, 5.
+- `1..=5`: An inclusive range. It includes all numbers from 1 to 5. It includes the last value, 5.
+- `1..`: An open-ended range. It includes all numbers from 1 to infinity (well, until the maximum value of the integer type).
+- `..5`: A range that starts at the minimum value for the integer type and ends at 4. It doesn't include the last value, 5.
+- `..=5`: A range that starts at the minimum value for the integer type and ends at 5. It includes the last value, 5.
+
+You can use a `for` loop with the first three kinds of ranges, where the starting point
+is explicitly specified. The last two range types are used in other contexts, that we'll cover later.
+
+The extreme values of a range don't have to be integer literals—they can be variables or expressions too!
+
+For example:
+
+```rust
+let end = 5;
+let mut sum = 0;
+
+for i in 1..(end + 1) {
+    sum += i;
+}
+```
+
+## Further reading
+
+- [`for` loop documentation](https://doc.rust-lang.org/std/keyword.for.html)
+
+[^iterator]: Later in the course we'll give a precise definition of what counts as an "iterator".
+For now, think of it as a sequence of values that you can loop over.
+[^weird-ranges]: You can use ranges with other types too (e.g. characters and IP addresses),
+but integers are definitely the most common case in day-to-day Rust programming.

ABasicCalculator/LoopsFor/lesson-info.yaml

@@ -0,0 +1,4 @@
+custom_name: Loops for
+content:
+  - Theory
+  - Task

ABasicCalculator/LoopsFor/lesson-remote-info.yaml

@@ -0,0 +1 @@
+id: 315334556

ABasicCalculator/LoopsWhile/Task/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "task_loops_while"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/LoopsWhile/Task/src/lib.rs

@@ -0,0 +1,17 @@
+// Rewrite the factorial function using a `while` loop.
+pub fn factorial(n: u32) -> u32 {
+    // The `todo!()` macro is a placeholder that the compiler
+    // interprets as "I'll get back to this later", thus
+    // suppressing type errors.
+    // It panics at runtime.
+    let mut i = 1;
+    let mut sum = 1;
+
+    while i <= n {
+        sum *= i;
+        i += 1;
+    }
+    sum
+
+
+}

ABasicCalculator/LoopsWhile/Task/task-info.yaml

@@ -0,0 +1,27 @@
+type: edu
+files:
+  - name: src/lib.rs
+    visible: true
+    placeholders:
+      - offset: 269
+        length: 110
+        placeholder_text: todo!()
+        initial_state:
+          length: 7
+          offset: 274
+        initialized_from_dependency: false
+        encrypted_possible_answer: E4RC0YxYtJ+r3XYct3/VbWhv0KY/DdVS2mEavS7NAeplIUze6rifYlz1/wF5ymecNIoK2ZQBm5WZbDVHNj0JjOi99JvSWj2HBmI6fZkCA4iDtsO00y8H7ja3yZio8lULMTOz/X12UEgThCYMWyBCTQ==
+        selected: true
+        status: Solved
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+  - name: tests/tests.rs
+    visible: false
+    learner_created: false
+status: Solved
+feedback:
+  message: 恭喜!
+  time: "Tue, 24 Feb 2026 09:10:50 UTC"
+record: -1

ABasicCalculator/LoopsWhile/Task/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 1557849382

ABasicCalculator/LoopsWhile/Task/task.md

@@ -0,0 +1,2 @@
+This task requires you to rewrite the `factorial` function.
+Previously, the `factorial` function was likely implemented using recursion. In this iteration, your goal is to reimplement the same functionality but using a `while` loop instead.

ABasicCalculator/LoopsWhile/Theory/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "theory_loops_while"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/LoopsWhile/Theory/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    // put your code here to launch it
+}

ABasicCalculator/LoopsWhile/Theory/task-info.yaml

@@ -0,0 +1,11 @@
+type: theory
+files:
+  - name: src/main.rs
+    visible: true
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+status: Solved
+record: -1
+post_submission_on_open: true

ABasicCalculator/LoopsWhile/Theory/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 99013028

ABasicCalculator/LoopsWhile/Theory/task.md

@@ -0,0 +1,85 @@
+## Loops, part 1: `while`
+
+Your implementation of `factorial` has been forced to use recursion.\
+This may feel natural to you, especially if you're coming from a functional programming background.
+Or it may feel strange, if you're used to more imperative languages like C or Python.
+
+Let's see how you can implement the same functionality using a **loop** instead.
+
+## The `while` loop
+
+A `while` loop is a way to execute a block of code as long as a **condition** is true.\
+Here's the general syntax:
+
+```rust
+while <condition> {
+    // code to execute
+}
+```
+
+For example, we might want to sum the numbers from 1 to 5:
+
+```rust
+let sum = 0;
+let i = 1;
+// "while i is less than or equal to 5"
+while i <= 5 {
+    // `+=` is a shorthand for `sum = sum + i`
+    sum += i;
+    i += 1;
+}
+```
+
+This will keep adding 1 to `i` and `i` to `sum` until `i` is no longer less than or equal to 5.
+
+## The `mut` keyword
+
+The example above won't compile as is. You'll get an error like:
+
+```text
+error[E0384]: cannot assign twice to immutable variable `sum`
+ --> src/main.rs:7:9
+  |
+2 |     let sum = 0;
+  |         ---
+  |         |
+  |         first assignment to `sum`
+  |         help: consider making this binding mutable: `mut sum`
+...
+7 |         sum += i;
+  |         ^^^^^^^^ cannot assign twice to immutable variable
+
+error[E0384]: cannot assign twice to immutable variable `i`
+ --> src/main.rs:8:9
+  |
+3 |     let i = 1;
+  |         -
+  |         |
+  |         first assignment to `i`
+  |         help: consider making this binding mutable: `mut i`
+...
+8 |         i += 1;
+  |         ^^^^^^ cannot assign twice to immutable variable
+```
+
+This is because variables in Rust are **immutable** by default.\
+You can't change their value once it has been assigned.
+
+If you want to allow modifications, you have to declare the variable as **mutable** using the `mut` keyword:
+
+```rust
+// `sum` and `i` are mutable now!
+let mut sum = 0;
+let mut i = 1;
+
+while i <= 5 {
+    sum += i;
+    i += 1;
+}
+```
+
+This will compile and run without errors.
+
+## Further reading
+
+- [`while` loop documentation](https://doc.rust-lang.org/std/keyword.while.html)

ABasicCalculator/LoopsWhile/lesson-info.yaml

@@ -0,0 +1,4 @@
+custom_name: Loops while
+content:
+  - Theory
+  - Task

ABasicCalculator/LoopsWhile/lesson-remote-info.yaml

@@ -0,0 +1 @@
+id: 178597809

ABasicCalculator/OverflowAndUnderflow/Task/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "task_overflow_and_underflow"
+version = "0.1.0"
+edition = "2021"

ABasicCalculator/OverflowAndUnderflow/Task/src/lib.rs

@@ -0,0 +1,8 @@
+pub fn factorial(n: u32) -> u32 {
+    let mut result: u32 = 1;
+    for i in 1..=n {
+        result = result.wrapping_mul(i);
+        /* TODO: Use wrapping_mul to ensure multiplication wraps around on overflow */
+    }
+    result
+}

ABasicCalculator/OverflowAndUnderflow/Task/task-info.yaml

@@ -0,0 +1,28 @@
+type: edu
+files:
+  - name: src/lib.rs
+    visible: true
+    placeholders:
+      - offset: 133
+        length: 78
+        placeholder_text: "/* TODO: Use wrapping_mul to ensure multiplication wraps around\
+      \ on overflow */"
+        initial_state:
+          length: 78
+          offset: 92
+        initialized_from_dependency: false
+        encrypted_possible_answer: zfLqC5JecSQrCUqhJOpCYXzRrrFwjAUqLYWmi8ftlzbNFqwi8fYglAnuG8NTy6M+
+        selected: true
+        status: Solved
+    learner_created: false
+  - name: Cargo.toml
+    visible: false
+    learner_created: false
+  - name: tests/tests.rs
+    visible: true
+    learner_created: false
+status: Solved
+feedback:
+  message: 恭喜!
+  time: "Tue, 24 Feb 2026 09:32:03 UTC"
+record: -1

ABasicCalculator/OverflowAndUnderflow/Task/task-remote-info.yaml

@@ -0,0 +1 @@
+id: 1321002669

ABasicCalculator/OverflowAndUnderflow/Task/task.md

@@ -0,0 +1 @@
+Adjust the `factorial` function so arithmetic overflows wrap around, matching the `twentieth()` test case's expected result for `factorial(20)`.

ABasicCalculator/OverflowAndUnderflow/Task/tests/tests.rs

@@ -0,0 +1,34 @@
+#[cfg(test)]
+mod tests {
+    use task_overflow_and_underflow::factorial;
+
+    #[test]
+    fn twentieth() {
+        // 20! is 2432902008176640000, which is too large to fit in a u32
+        // With the default dev profile, this will panic when you run `cargo test`
+        // We want it to wrap around instead
+        assert_eq!(factorial(20), 2_192_834_560);
+        //                           ☝️
+        // A large number literal using underscores to improve readability!
+    }
+
+    #[test]
+    fn first() {
+        assert_eq!(factorial(0), 1);
+    }
+
+    #[test]
+    fn second() {
+        assert_eq!(factorial(1), 1);
+    }
+
+    #[test]
+    fn third() {
+        assert_eq!(factorial(2), 2);
+    }
+
+    #[test]
+    fn fifth() {
+        assert_eq!(factorial(5), 120);
+    }
+}