update: 完成 14 题

Signed-off-by: YdrMaster <[email protected]>

exercises/06_loop/main.cpp

@@ -3,10 +3,10 @@
 // TODO: 改正函数实现，实现正确的缓存优化斐波那契计算
 static unsigned long long fibonacci(int i) {
     // TODO: 为缓存设置正确的初始值
-    static unsigned long long cache[128], next = 2;
+    static unsigned long long cache[128], cached = 2;
     // TODO: 设置正确的循环条件
-    for (; false; ++next) {
-        cache[next] = cache[next - 1] + cache[next - 2];
+    for (; false; ++cached) {
+        cache[cached] = cache[cached - 1] + cache[cached - 2];
     }
     return cache[i];
 }

exercises/08_trivial/main.cpp

@@ -3,13 +3,13 @@
 // READ: Trivial type <https://learn.microsoft.com/en-us/cpp/cpp/trivial-standard-layout-and-pod-types?view=msvc-170>
 struct FibonacciCache {
     unsigned long long cache[16];
-    int next;
+    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 (;; ++next) {
-        cache[next] = cache[next - 1] + cache[next - 2];
+    for (;; ++cached) {
+        cache[cached] = cache[cached - 1] + cache[cached - 2];
     }
     return cache.cache[i];
 }

exercises/09_method/main.cpp

@@ -2,12 +2,12 @@
 
 struct Fibonacci {
     unsigned long long cache[128];
-    int next;
+    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 (; false; ++next) {
-            cache[next] = cache[next - 1] + cache[next - 2];
+        for (; false; ++cached) {
+            cache[cached] = cache[cached - 1] + cache[cached - 2];
         }
         return cache[i];
     }

exercises/11_class/main.cpp

@@ -1,23 +1,35 @@
 #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[128];
-    int next = 2;
+    size_t cache[16];
+    int cached;
 
 public:
-    Fibonacci() : cache{0, 1}, next(2) {}
+    // TODO: 实现构造器
+    // Fibonacci()
 
-    size_t operator[](int i) {
-        for (; next <= i; ++next) {
-            cache[next] = cache[next - 1] + cache[next - 2];
+    // 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];
         }
         return cache[i];
     }
 };
 
 int main(int argc, char **argv) {
-    Fibonacci fib0, fib1;
-    std::cout << "fibonacci(10) = " << fib0[10] << std::endl;
-    std::cout << "fibonacci(100) = " << fib1[100] << std::endl;
+    // 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;
 }

exercises/12_class_deconstruct/main.cpp

@@ -0,0 +1,32 @@
+#include "../exercise.h"
+
+// READ: 析构函数 <https://zh.cppreference.com/w/cpp/language/destructor>
+
+/// @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(?) {}
+
+    // TODO: 实现析构器，释放缓存空间
+    ~DynFibonacci();
+
+    // 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];
+        }
+        return cache[i];
+    }
+};
+
+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;
+    return 0;
+}

exercises/13_class_clone/main.cpp

@@ -0,0 +1,45 @@
+#include "../exercise.h"
+
+// READ: 复制构造函数 <https://zh.cppreference.com/w/cpp/language/copy_constructor>
+
+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(?) {}
+
+    // TODO: 实现复制构造器
+    DynFibonacci(DynFibonacci const &other) = delete;
+
+    // TODO: 实现析构器，释放缓存空间
+    ~DynFibonacci();
+
+    // 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];
+        }
+        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];
+        }
+        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");
+    DynFibonacci const fib_ = fib;
+    ASSERT(fib_.get(10) == fib.get(10), "Object cloned");
+    return 0;
+}

exercises/14_class_move/main.cpp

@@ -0,0 +1,55 @@
+#include "../exercise.h"
+
+// READ: 移动构造函数 <https://zh.cppreference.com/w/cpp/language/move_constructor>
+// READ: 移动赋值 <https://zh.cppreference.com/w/cpp/language/move_assignment>
+// READ: 运算符重载 <https://zh.cppreference.com/w/cpp/language/operators>
+
+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(?) {}
+
+    // TODO: 实现移动构造器
+    DynFibonacci(DynFibonacci &&other) noexcept = delete;
+
+    // TODO: 实现移动赋值
+    // NOTICE: ⚠ 注意移动到自身问题 ⚠
+    DynFibonacci &operator=(DynFibonacci &&other) noexcept = delete;
+
+    // TODO: 实现析构器，释放缓存空间
+    ~DynFibonacci();
+
+    // TODO: 实现正确的缓存优化斐波那契计算
+    size_t operator[](int i) {
+        for (; false; ++cached) {
+            cache[cached] = cache[cached - 1] + cache[cached - 2];
+        }
+        return cache[i];
+    }
+
+    // NOTICE: 不要修改这个方法
+    bool is_alive() const {
+        return cache;
+    }
+};
+
+int main(int argc, char **argv) {
+    DynFibonacci fib(12);
+    ASSERT(fib[10] == 55, "fibonacci(10) should be 55");
+
+    DynFibonacci const fib_ = std::move(fib);
+    ASSERT(!fib.is_alive(), "Object moved");
+    ASSERT(fib_[10] == 55, "fibonacci(10) should be 55");
+
+    DynFibonacci fib0(6);
+    DynFibonacci fib1(12);
+
+    fib0 = std::move(fib1);
+    fib0 = std::move(fib0);
+    ASSERT(fib0[10] == 55, "fibonacci(10) should be 55");
+
+    return 0;
+}

exercises/xmake.lua

@@ -44,3 +44,19 @@ target("exercise09")
 target("exercise10")
     set_kind("binary")
     add_files("10_method_const/main.cpp")
+
+target("exercise11")
+    set_kind("binary")
+    add_files("11_class/main.cpp")
+
+target("exercise12")
+    set_kind("binary")
+    add_files("12_class_deconstruct/main.cpp")
+
+target("exercise13")
+    set_kind("binary")
+    add_files("13_class_clone/main.cpp")
+
+target("exercise14")
+    set_kind("binary")
+    add_files("14_class_move/main.cpp")

learn/summary.cpp

@@ -5,7 +5,7 @@
 #include <sstream>
 #include <vector>
 
-constexpr auto MAX_EXERCISE = 10;
+constexpr auto MAX_EXERCISE = 14;
 
 int main(int argc, char **argv) {
     if (argc == 1) {