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exercises/exercises/00_hello_world/main.cpp

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+#include "../exercise.h"
+
+// READ: std streams <https://zh.cppreference.com/w/cpp/io/c/std_streams>
+// READ: 流修饰符 <https://zh.cppreference.com/w/cpp/io/manip>
+// READ: format in cxx20 <https://zh.cppreference.com/w/cpp/utility/format/format>
+
+int main(int argc, char **argv) {
+    // TODO: 在控制台输出 "Hello, InfiniTensor!" 并换行
+    std::cout << "Hello, InfiniTensor!" <<std::endl;
+    return 0;
+}

exercises/exercises/01_variable&add/main.cpp

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+#include "../exercise.h"
+
+// READ: 运算符 <https://zh.cppreference.com/w/cpp/language/expressions#.E8.BF.90.E7.AE.97.E7.AC.A6>
+
+int main(int argc, char **argv) {
+    // TODO: 补全变量定义并打印加法运算
+    // x ?
+    int x=5;
+    std::cout << x << " + " << x << " = " << x + x << std::endl;
+    return 0;
+}

exercises/exercises/02_function/main.cpp

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+#include "../exercise.h"
+
+// READ: 声明 <https://zh.cppreference.com/w/cpp/language/declarations>
+// NOTICE: cppreference 中的示例中指出了复杂声明的解读法，建议认真阅读。
+// NOTICE: 补充由内而外读法的机翻解释 <https://learn.microsoft.com/zh-cn/cpp/c-language/interpreting-more-complex-declarators?view=msvc-170>
+
+// TODO: 在这里声明函数
+int add(int x,int y);
+int main(int argc, char **argv) {
+    ASSERT(add(123, 456) == 123 + 456, "add(123, 456) should be 123 + 456");
+
+    auto x = 1, y = 2;
+    std::cout << x << " + " << y << " = " << add(x, y) << std::endl;
+    return 0;
+}
+
+int add(int a, int b) {
+    // TODO: 补全函数定义，但不要移动代码行
+    return a+b;
+}

exercises/exercises/03_argument&parameter/main.cpp

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+#include "../exercise.h"
+
+// READ: <https://stackoverflow.com/questions/156767/whats-the-difference-between-an-argument-and-a-parameter>
+// THINK: 参数都有哪些传递方式？如何选择传递方式？
+
+void func(int);
+
+// TODO: 为下列 ASSERT 填写正确的值
+int main(int argc, char **argv) {
+    auto arg = 99;
+    ASSERT(arg == 99, "arg should be ?");
+    std::cout << "befor func call: " << arg << std::endl;
+    func(arg);
+    ASSERT(arg == 99, "arg should be ?");
+    std::cout << "after func call: " << arg << std::endl;
+    return 0;
+}
+
+// TODO: 为下列 ASSERT 填写正确的值
+void func(int param) {
+    ASSERT(param == 99, "param should be ?");
+    std::cout << "befor add: " << param << std::endl;
+    param += 1;
+    ASSERT(param == 100, "param should be ?");
+    std::cout << "after add: " << param << std::endl;
+}

exercises/exercises/04_static/main.cpp

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+#include "../exercise.h"
+
+// READ: `static` 关键字 <https://zh.cppreference.com/w/cpp/language/storage_duration>
+// THINK: 这个函数的两个 `static` 各自的作用是什么？
+static int func(int param) {
+    static int static_ = param;
+    // std::cout << "static_ = " << static_ << std::endl;
+    return static_++;
+}
+
+int main(int argc, char **argv) {
+    // TODO: 将下列 `?` 替换为正确的数字
+    ASSERT(func(5) == 5, "static variable value incorrect");
+    ASSERT(func(4) == 6, "static variable value incorrect");
+    ASSERT(func(3) == 7, "static variable value incorrect");
+    ASSERT(func(2) == 8, "static variable value incorrect");
+    ASSERT(func(1) == 9, "static variable value incorrect");
+    return 0;
+}

exercises/exercises/05_constexpr/main.cpp

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+#include "../exercise.h"
+
+constexpr unsigned long long fibonacci(int i) {
+    switch (i) {
+        case 0:
+            return 0;
+        case 1:
+            return 1;
+        default:
+            return fibonacci(i - 1) + fibonacci(i - 2);
+    }
+}
+
+int main(int argc, char **argv) {
+    constexpr auto FIB20 = fibonacci(20);
+    ASSERT(FIB20 == 6765, "fibonacci(20) should be 6765");
+    std::cout << "fibonacci(20) = " << FIB20 << std::endl;
+
+    // TODO: 观察错误信息，修改一处，使代码编译运行
+    // PS: 编译运行，但是不一定能算出结果……
+    constexpr auto ANS_N = 10;
+    constexpr auto ANS = fibonacci(ANS_N);
+    std::cout << "fibonacci(" << ANS_N << ") = " << ANS << std::endl;
+
+    return 0;
+}

exercises/exercises/06_array/main.cpp

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+#include "../exercise.h"
+
+// READ: 数组 <https://zh.cppreference.com/w/cpp/language/array>
+
+unsigned long long arr[90]{0, 1};
+unsigned long long fibonacci(int i) {
+    switch (i) {
+        case 0:
+            return 0;
+        case 1:
+            return 1;
+        default:
+            // TODO: 补全三目表达式缺失的部分
+            return arr[i] ? arr[i] : (arr[i] = fibonacci(i - 1) + fibonacci(i - 2));
+    }
+}
+
+int main(int argc, char **argv) {
+    // TODO: 为此 ASSERT 填写正确的值
+    ASSERT(sizeof(arr) == 720, "sizeof array is size of all its elements");
+    // ---- 不要修改以下代码 ----
+    ASSERT(fibonacci(2) == 1, "fibonacci(2) should be 1");
+    ASSERT(fibonacci(20) == 6765, "fibonacci(20) should be 6765");
+    ASSERT(fibonacci(80) == 23416728348467685, "fibonacci(80) should be 23416728348467685");
+    return 0;
+}

exercises/exercises/07_loop/main.cpp

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+#include "../exercise.h"
+
+// TODO: 改正函数实现，实现正确的缓存优化斐波那契计算
+// THINk: 这个函数是一个纯函数（pure function）吗？
+// READ: 纯函数 <https://zh.wikipedia.org/wiki/%E7%BA%AF%E5%87%BD%E6%95%B0>
+static unsigned long long fibonacci(int i) {
+    // TODO: 为缓存设置正确的初始值
+    static unsigned long long cache[96]{0,1}, cached=2;
+    // TODO: 设置正确的循环条件
+    for (; cached<=i; ++cached) {
+        cache[cached] = cache[cached - 1] + cache[cached - 2];
+    }
+    return cache[i];
+}
+
+// ---- 不要修改以下代码 ----
+int main(int argc, char **argv) {
+    ASSERT(fibonacci(0) == 0, "fibonacci(0) should be 0");
+    ASSERT(fibonacci(1) == 1, "fibonacci(1) should be 1");
+    ASSERT(fibonacci(2) == 1, "fibonacci(2) should be 1");
+    ASSERT(fibonacci(3) == 2, "fibonacci(3) should be 2");
+    ASSERT(fibonacci(10) == 55, "fibonacci(10) should be 55");
+
+    auto fib90 = fibonacci(90);
+    std::cout << "fibonacci(90) = " << fib90 << std::endl;
+    ASSERT(fib90 == 2880067194370816120, "fibonacci(90) should be 2880067194370816120");
+    return 0;
+}

exercises/exercises/08_pointer/main.cpp

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+#include "../exercise.h"
+
+// READ: 数组向指针退化 <https://zh.cppreference.com/w/cpp/language/array#%E6%95%B0%E7%BB%84%E5%88%B0%E6%8C%87%E9%92%88%E7%9A%84%E9%80%80%E5%8C%96>
+bool is_fibonacci(int *ptr, int len, int stride) {
+    ASSERT(len >= 3, "`len` should be at least 3");
+    // TODO: 编写代码判断从 ptr 开始，每 stride 个元素取 1 个元素，组成长度为 n 的数列是否满足
+    // arr[i + 2] = arr[i] + arr[i + 1]
+
+    for(int i=2;i<len;i++){
+      int *pre1=ptr+((i-1)*stride);
+      int *pre2=ptr+((i-2)*stride);
+      int *cur=ptr+((i)*stride);
+      if(*cur!=*pre1+*pre2)return false;
+    }
+    return true;
+}
+
+// ---- 不要修改以下代码 ----
+int main(int argc, char **argv) {
+    int arr0[]{0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55},
+        arr1[]{0, 1, 2, 3, 4, 5, 6},
+        arr2[]{99, 98, 4, 1, 7, 2, 11, 3, 18, 5, 29, 8, 47, 13, 76, 21, 123, 34, 199, 55, 322, 0, 0};
+    // clang-format off
+    ASSERT( is_fibonacci(arr0    , sizeof(arr0) / sizeof(*arr0)    , 1),         "arr0 is Fibonacci"    );
+    ASSERT( is_fibonacci(arr0 + 2, sizeof(arr0) / sizeof(*arr0) - 4, 1), "part of arr0 is Fibonacci"    );
+    ASSERT(!is_fibonacci(arr1    , sizeof(arr1) / sizeof(*arr1)    , 1),         "arr1 is not Fibonacci");
+    ASSERT( is_fibonacci(arr1 + 1,  3                              , 1), "part of arr1 is Fibonacci"    );
+    ASSERT(!is_fibonacci(arr2    , sizeof(arr2) / sizeof(*arr2)    , 1),         "arr2 is not Fibonacci");
+    ASSERT( is_fibonacci(arr2 + 2, 10                              , 2), "part of arr2 is Fibonacci"    );
+    ASSERT( is_fibonacci(arr2 + 3,  9                              , 2), "part of arr2 is Fibonacci"    );
+    ASSERT(!is_fibonacci(arr2 + 3, 10                              , 2), "guard check"                  );
+    ASSERT(!is_fibonacci(arr2 + 1, 10                              , 2), "guard check"                  );
+    // clang-format on
+    return 0;
+}

exercises/exercises/09_enum&union/main.cpp

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+#include "../exercise.h"
+
+// READ: 枚举类型 <https://zh.cppreference.com/w/cpp/language/enum>
+
+// `enum` 是 C 的兼容类型，本质上其对应类型的常量。
+// 在 `enum` 中定义标识符等价于定义 constexpr 常量，
+// 这些标识符不需要前缀，可以直接引用。
+// 因此 `enum` 定义会污染命名空间。
+enum ColorEnum : unsigned char {
+    COLOR_RED = 31,
+    COLOR_GREEN,
+    COLOR_YELLOW,
+    COLOR_BLUE,
+};
+
+// 有作用域枚举型是 C++ 引入的类型安全枚举。
+// 其内部标识符需要带前缀引用，如 `Color::Red`。
+// 作用域枚举型可以避免命名空间污染，并提供类型安全保证。
+enum class Color : int {
+    Red = COLOR_RED,
+    Green,
+    Yellow,
+    Blue,
+};
+
+ColorEnum convert_by_pun(Color c) {
+    // READ: <https://zh.cppreference.com/w/cpp/language/union>
+    // `union` 表示在同一内存位置存储的不同类型的值。
+    // 其常见用法是实现类型双关转换，即将一种类型的值转换为另一种无关类型的值。
+    // 但这种写法实际上仅在 C 语言良定义，在 C++ 中是未定义行为。
+    // 这是比较少见的 C++ 不与 C 保持兼容的特性。
+    // READ: 类型双关 <https://tttapa.github.io/Pages/Programming/Cpp/Practices/type-punning.html>
+    union TypePun {
+        ColorEnum e;
+        Color c;
+    };
+
+    TypePun pun;
+    // TODO: 补全类型双关转换
+    pun.c=c;
+    return pun.e;
+}
+
+int main(int argc, char **argv) {
+    ASSERT(convert_by_pun(Color::Red) == COLOR_RED, "Type punning conversion");
+    ASSERT(convert_by_pun(Color::Green) == COLOR_GREEN, "Type punning conversion");
+    ASSERT(convert_by_pun(Color::Yellow) == COLOR_YELLOW, "Type punning conversion");
+    ASSERT(convert_by_pun(Color::Blue) == COLOR_BLUE, "Type punning conversion");
+    return 0;
+}

exercises/exercises/10_trivial/main.cpp

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+#include "../exercise.h"
+
+// READ: Trivial type <https://learn.microsoft.com/zh-cn/cpp/cpp/trivial-standard-layout-and-pod-types?view=msvc-170>
+
+struct FibonacciCache {
+    unsigned long long cache[16];
+    int cached;
+};
+
+// TODO: 实现正确的缓存优化斐波那契计算
+static unsigned long long fibonacci(FibonacciCache &cache, int i) {
+    for (;cache.cached<=i ; ++cache.cached) {
+        cache.cache[cache.cached] = cache.cache[cache.cached - 1] + cache.cache[cache.cached - 2];
+    }
+    return cache.cache[i];
+}
+
+int main(int argc, char **argv) {
+    // TODO: 初始化缓存结构体，使计算正确
+    // NOTICE: C/C++ 中，读取未初始化的变量（包括结构体变量）是未定义行为
+    // READ: 初始化的各种写法 <https://zh.cppreference.com/w/cpp/language/initialization>
+    FibonacciCache fib={{0,1},2};
+    ASSERT(fibonacci(fib, 10) == 55, "fibonacci(10) should be 55");
+    std::cout << "fibonacci(10) = " << fibonacci(fib, 10) << std::endl;
+    return 0;
+}

exercises/exercises/11_method/main.cpp

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+#include "../exercise.h"
+
+struct Fibonacci {
+    unsigned long long cache[128];
+    int cached;
+
+    // TODO: 实现正确的缓存优化斐波那契计算
+     unsigned long long get(int i) {
+        for (; cached<=i; ++cached) {
+            cache[cached] = cache[cached - 1] + cache[cached - 2];
+        }
+        return cache[i];
+    }
+};
+
+int main(int argc, char **argv) {
+    // TODO: 初始化缓存结构体，使计算正确
+    Fibonacci fib={{0,1},2};
+    ASSERT(fib.get(10) == 55, "fibonacci(10) should be 55");
+    std::cout << "fibonacci(10) = " << fib.get(10) << std::endl;
+    return 0;
+}

exercises/exercises/12_method_const/main.cpp

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+#include "../exercise.h"
+
+// READ: 有 cv 限定符的成员函数 <https://zh.cppreference.com/w/cpp/language/member_functions>
+
+struct Fibonacci {
+    int numbers[11];
+    // TODO: 修改方法签名和实现，使测试通过
+    constexpr int get(int i) const {
+      return numbers[i];
+    }
+};
+
+int main(int argc, char **argv) {
+    Fibonacci constexpr FIB{{0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55}};
+    ASSERT(FIB.get(10) == 55, "fibonacci(10) should be 55");
+    std::cout << "fibonacci(10) = " << FIB.get(10) << std::endl;
+    return 0;
+}

exercises/exercises/13_class/main.cpp

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+#include "../exercise.h"
+
+// C++ 中，`class` 和 `struct` 之间的**唯一区别**是
+// `class` 默认访问控制符是 `private`，
+// `struct` 默认访问控制符是 `public`。
+// READ: 访问说明符 <https://zh.cppreference.com/w/cpp/language/access>
+
+// 这个 class 中的字段被 private 修饰，只能在 class 内部访问。
+// 因此必须提供构造器来初始化字段。
+// READ: 构造器 <https://zh.cppreference.com/w/cpp/language/constructor>
+class Fibonacci {
+    size_t cache[16];
+    int cached;
+
+public:
+    // TODO: 实现构造器
+    Fibonacci(){
+      cache[0]=0;
+      cache[1]=1;
+      cached=2;
+    }
+
+    // TODO: 实现正确的缓存优化斐波那契计算
+    size_t get(int i) {
+        for (; cached<=i; ++cached) {
+            cache[cached] = cache[cached - 1] + cache[cached - 2];
+        }
+        return cache[i];
+    }
+};
+
+int main(int argc, char **argv) {
+    // 现在类型拥有无参构造器，声明时会直接调用。
+    // 这个写法不再是未定义行为了。
+    Fibonacci fib;
+    ASSERT(fib.get(10) == 55, "fibonacci(10) should be 55");
+    std::cout << "fibonacci(10) = " << fib.get(10) << std::endl;
+    return 0;
+}