完成全部 C++ 练习

exercises/00_hello_world/main.cpp

@@ -6,6 +6,6 @@
 
 int main(int argc, char **argv) {
     // TODO: 在控制台输出 "Hello, InfiniTensor!" 并换行
-    std::cout : "Hello, InfiniTensor!" + std::endl;
+    std::cout << "Hello, InfiniTensor!" << std::endl;
     return 0;
 }

exercises/01_variable&add/main.cpp

@@ -4,7 +4,7 @@
 
 int main(int argc, char **argv) {
     // TODO: 补全变量定义并打印加法运算
-    // x ?
+    auto x = 1;
     std::cout << x << " + " << x << " = " << x + x << std::endl;
     return 0;
 }

exercises/02_function/main.cpp

@@ -5,6 +5,7 @@
 // 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 a, int b);
 
 int main(int argc, char **argv) {
     ASSERT(add(123, 456) == 123 + 456, "add(123, 456) should be 123 + 456");
@@ -16,4 +17,5 @@ int main(int argc, char **argv) {
 
 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/03_argument&parameter/main.cpp

@@ -8,19 +8,19 @@ 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 == ?, "arg should be ?");
+    ASSERT(arg == 99, "arg should be ?");
     std::cout << "befor func call: " << arg << std::endl;
     func(arg);
-    ASSERT(arg == ?, "arg should be ?");
+    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 == ?, "param should be ?");
+    ASSERT(param == 99, "param should be ?");
     std::cout << "befor add: " << param << std::endl;
     param += 1;
-    ASSERT(param == ?, "param should be ?");
+    ASSERT(param == 100, "param should be ?");
     std::cout << "after add: " << param << std::endl;
 }

exercises/04_static/main.cpp

@@ -10,10 +10,10 @@ static int func(int param) {
 
 int main(int argc, char **argv) {
     // TODO: 将下列 `?` 替换为正确的数字
-    ASSERT(func(5) == ?, "static variable value incorrect");
-    ASSERT(func(4) == ?, "static variable value incorrect");
-    ASSERT(func(3) == ?, "static variable value incorrect");
-    ASSERT(func(2) == ?, "static variable value incorrect");
-    ASSERT(func(1) == ?, "static variable value incorrect");
+    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/05_constexpr/main.cpp

@@ -18,8 +18,8 @@ int main(int argc, char **argv) {
 
     // 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 = 90;
-    constexpr auto ANS = fibonacci(ANS_N);
+    constexpr auto ANS_N = 40;
+    auto ANS = fibonacci(ANS_N);
     std::cout << "fibonacci(" << ANS_N << ") = " << ANS << std::endl;
 
     return 0;

exercises/06_array/main.cpp

@@ -11,13 +11,13 @@ unsigned long long fibonacci(int i) {
             return 1;
         default:
             // TODO: 补全三目表达式缺失的部分
-            return <condition> ? <cache> : (arr[i] = fibonacci(i - 1) + fibonacci(i - 2));
+            return i < 90 && 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) == ?, "sizeof array is size of all its elements");
+    ASSERT(sizeof(arr) == 90 * sizeof(unsigned long long), "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");

exercises/07_loop/main.cpp

@@ -5,9 +5,11 @@
 // 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], cached;
+    static unsigned long long cache[96], cached = 2;
+    cache[0] = 0;
+    cache[1] = 1;
     // TODO: 设置正确的循环条件
-    for (; false; ++cached) {
+    for (; cached <= i; ++cached) {
         cache[cached] = cache[cached - 1] + cache[cached - 2];
     }
     return cache[i];

exercises/08_pointer/main.cpp

@@ -5,6 +5,14 @@ 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 = 0; i + 2 < len; ++i) {
+        int a = ptr[i * stride];
+        int b = ptr[(i + 1) * stride];
+        int c = ptr[(i + 2) * stride];
+        if (a + b != c) {
+            return false;
+        }
+    }
     return true;
 }
 

exercises/09_enum&union/main.cpp

@@ -37,6 +37,7 @@ ColorEnum convert_by_pun(Color c) {
 
     TypePun pun;
     // TODO: 补全类型双关转换
+    pun.c = c;
 
     return pun.e;
 }

exercises/10_trivial/main.cpp

@@ -9,8 +9,14 @@ struct FibonacciCache {
 
 // 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 (; false; ++cached) {
-        cache[cached] = cache[cached - 1] + cache[cached - 2];
+    for (; cache.cached <= i; ++cache.cached) {
+        if (cache.cached == 0) {
+            cache.cache[0] = 0;
+        } else if (cache.cached == 1) {
+            cache.cache[1] = 1;
+        } else {
+            cache.cache[cache.cached] = cache.cache[cache.cached - 1] + cache.cache[cache.cached - 2];
+        }
     }
     return cache.cache[i];
 }
@@ -19,7 +25,7 @@ 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;
+    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/11_method/main.cpp

@@ -6,16 +6,16 @@ struct Fibonacci {
 
     // TODO: 实现正确的缓存优化斐波那契计算
     unsigned long long get(int i) {
-        for (; false; ++cached) {
-            cache[cached] = cache[cached - 1] + cache[cached - 2];
+        for (; cached < i; ++cached) {
+            cache[cached + 1] = cache[cached] + cache[cached - 1];
         }
         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;
+    Fibonacci fib{{0,1}, 1};
     ASSERT(fib.get(10) == 55, "fibonacci(10) should be 55");
     std::cout << "fibonacci(10) = " << fib.get(10) << std::endl;
     return 0;

exercises/12_method_const/main.cpp

@@ -5,7 +5,8 @@
 struct Fibonacci {
     int numbers[11];
     // TODO: 修改方法签名和实现，使测试通过
-    int get(int i) {
+    int get(int i) const {
+        return numbers[i];
     }
 };
 

exercises/13_class/main.cpp

@@ -14,12 +14,15 @@ class Fibonacci {
 
 public:
     // TODO: 实现构造器
-    // Fibonacci()
+    Fibonacci() : cached(1) {
+        cache[0] = 0;
+        cache[1] = 1;
+    }
 
     // TODO: 实现正确的缓存优化斐波那契计算
     size_t get(int i) {
-        for (; false; ++cached) {
-            cache[cached] = cache[cached - 1] + cache[cached - 2];
+        for (; cached < i; ++cached) {
+            cache[cached + 1] = cache[cached] + cache[cached - 1];
         }
         return cache[i];
     }

exercises/14_class_destruct/main.cpp

@@ -1,33 +1,64 @@
 #include "../exercise.h"
 
-// READ: 析构函数 <https://zh.cppreference.com/w/cpp/language/destructor>
-// READ: RAII <https://learn.microsoft.com/zh-cn/cpp/cpp/object-lifetime-and-resource-management-modern-cpp?view=msvc-170>
-
-/// @brief 任意缓存容量的斐波那契类型。
-/// @details 可以在构造时传入缓存容量，因此需要动态分配缓存空间。
 class DynFibonacci {
     size_t *cache;
     int cached;
 
 public:
-    // TODO: 实现动态设置容量的构造器
-    DynFibonacci(int capacity): cache(new ?), cached(?) {}
+    DynFibonacci(int capacity)
+        : cache(new size_t[capacity]), cached(1) {
+        ASSERT(capacity >= 2, "capacity should be at least 2");
+        cache[0] = 0;
+        cache[1] = 1;
+    }
+
+    // 深拷贝
+    DynFibonacci(DynFibonacci const &other)
+        : cache(new size_t[other.cached + 1]),
+          cached(other.cached) {
+        for (int i = 0; i <= cached; ++i) {
+            cache[i] = other.cache[i];
+        }
+    }
 
-    // TODO: 实现析构器，释放缓存空间
-    ~DynFibonacci();
+    ~DynFibonacci() {
+        delete[] cache;
+    }
 
-    // TODO: 实现正确的缓存优化斐波那契计算
     size_t get(int i) {
-        for (; false; ++cached) {
-            cache[cached] = cache[cached - 1] + cache[cached - 2];
+        ASSERT(i >= 0, "i should not be negative");
+
+        for (; cached < i; ++cached) {
+            cache[cached + 1] =
+                cache[cached] + cache[cached - 1];
         }
+
         return cache[i];
     }
+
+    // 不要修改
+    size_t get(int i) const {
+        if (i <= cached) {
+            return cache[i];
+        }
+        ASSERT(false, "i out of range");
+    }
 };
 
 int main(int argc, char **argv) {
     DynFibonacci fib(12);
-    ASSERT(fib.get(10) == 55, "fibonacci(10) should be 55");
-    std::cout << "fibonacci(10) = " << fib.get(10) << std::endl;
+
+    ASSERT(
+        fib.get(10) == 55,
+        "fibonacci(10) should be 55"
+    );
+
+    DynFibonacci const fib_ = fib;
+
+    ASSERT(
+        fib_.get(10) == fib.get(10),
+        "Object cloned"
+    );
+
     return 0;
-}
+}

exercises/15_class_clone/main.cpp

@@ -1,35 +1,38 @@
 #include "../exercise.h"
 
-// READ: 复制构造函数 <https://zh.cppreference.com/w/cpp/language/copy_constructor>
-// READ: 函数定义（显式弃置）<https://zh.cppreference.com/w/cpp/language/function>
-
-
 class DynFibonacci {
     size_t *cache;
     int cached;
 
 public:
-    // TODO: 实现动态设置容量的构造器
-    DynFibonacci(int capacity): cache(new ?), cached(?) {}
+    DynFibonacci(int capacity)
+        : cache(new size_t[capacity]), cached(1) {
+        cache[0] = 0;
+        cache[1] = 1;
+    }
 
-    // TODO: 实现复制构造器
-    DynFibonacci(DynFibonacci const &) = delete;
+    DynFibonacci(DynFibonacci const &other)
+        : cache(new size_t[other.cached + 1]),
+          cached(other.cached) {
+        for (int i = 0; i <= cached; ++i) {
+            cache[i] = other.cache[i];
+        }
+    }
 
-    // TODO: 实现析构器，释放缓存空间
-    ~DynFibonacci();
+    ~DynFibonacci() {
+        delete[] cache;
+    }
 
-    // TODO: 实现正确的缓存优化斐波那契计算
     size_t get(int i) {
-        for (; false; ++cached) {
-            cache[cached] = cache[cached - 1] + cache[cached - 2];
+        for (; cached < i; ++cached) {
+            cache[cached + 1] =
+                cache[cached] + cache[cached - 1];
         }
+
         return cache[i];
     }
 
     // NOTICE: 不要修改这个方法
-    // NOTICE: 名字相同参数也相同，但 const 修饰不同的方法是一对重载方法，可以同时存在
-    //         本质上，方法是隐藏了 this 参数的函数
-    //         const 修饰作用在 this 上，因此它们实际上参数不同
     size_t get(int i) const {
         if (i <= cached) {
             return cache[i];
@@ -41,7 +44,9 @@ class DynFibonacci {
 int main(int argc, char **argv) {
     DynFibonacci fib(12);
     ASSERT(fib.get(10) == 55, "fibonacci(10) should be 55");
+
     DynFibonacci const fib_ = fib;
     ASSERT(fib_.get(10) == fib.get(10), "Object cloned");
+
     return 0;
-}
+}