学懂C++（五十三）：全面解析：C++11 标准及其新特性详解

#include <iostream>
#include <vector>class Resource {
public:int* data;Resource() {data = new int[1000];  // 动态分配资源std::cout << "Resource acquired" << std::endl;}~Resource() {delete[] data;  // 释放资源std::cout << "Resource destroyed" << std::endl;}// 移动构造函数Resource(Resource&& other) noexcept : data(other.data) {other.data = nullptr;  // 让源对象不再拥有资源std::cout << "Resource moved" << std::endl;}// 禁用复制构造函数Resource(const Resource&) = delete;
};int main() {std::vector<Resource> vec;vec.push_back(Resource());  // 触发移动构造函数return 0;
}

#include <iostream>
#include <vector>int main() {std::vector<int> nums = {1, 2, 3, 4, 5};// 使用基于范围的 for 循环迭代for (int num : nums) {std::cout << num << " ";  // 输出 1 2 3 4 5}return 0;
}

#include <iostream>
#include <vector>struct Point {int x, y;
};int main() {// 用列表初始化基本类型int arr[3] = {1, 2, 3};// 初始化容器std::vector<int> vec = {1, 2, 3, 4};// 初始化结构体Point p = {10, 20};// 输出std::cout << "Point: (" << p.x << ", " << p.y << ")" << std::endl;return 0;
}

#include <iostream>enum class Color { Red, Green, Blue };
enum class Fruit { Apple, Orange, Banana };int main() {Color color = Color::Red;Fruit fruit = Fruit::Apple;// 错误：不能隐式转换 enum class 类型// int colorValue = color;// 正确：显式转换为整数int colorValue = static_cast<int>(color);std::cout << "Color value: " << colorValue << std::endl;  // 输出 0return 0;
}

#include <iostream>template<typename T>
void checkType() {static_assert(sizeof(T) == 4, "Type size must be 4 bytes");
}int main() {checkType<int>();  // 正确：int 通常是 4 字节// checkType<double>();  // 错误：double 通常不是 4 字节，编译期断言失败return 0;
}

#include <iostream>class MyClass {
public:MyClass(int value) : value_(value) {std::cout << "Constructor with int" << std::endl;}MyClass() : MyClass(0) {  // 委托构造函数std::cout << "Default constructor" << std::endl;}private:int value_;
};int main() {MyClass obj1;        // 调用默认构造函数MyClass obj2(10);    // 调用带参数的构造函数return 0;
}

#include <iostream>class Base {
public:Base(int value) : value_(value) {std::cout << "Base constructor" << std::endl;}private:int value_;
};class Derived : public Base {
public:using Base::Base;  // 继承基类构造函数
};int main() {Derived obj(10);  // 调用基类构造函数return 0;
}

#include <iostream>template<typename T>
void print(T t) {std::cout << t << std::endl;
}template<typename T, typename... Args>
void print(T t, Args... args) {std::cout << t << " ";print(args...);  // 递归调用，继续处理剩余的参数
}int main() {print(1, 2.5, "Hello", 'A');  // 输出 1 2.5 Hello Areturn 0;
}

#include <iostream>
#include <memory>int main() {std::unique_ptr<int> p1(new int(10));  // 创建 unique_ptrstd::cout << *p1 << std::endl;  // 输出 10// 转移所有权std::unique_ptr<int> p2 = std::move(p1);std::cout << (p1 ? "p1 not null" : "p1 null") << std::endl;  // 输出 "p1 null"return 0;
}

#include <iostream>
#include <memory>int main() {std::shared_ptr<int> sp1(new int(20));std::shared_ptr<int> sp2 = sp1;  // 共享所有权std::cout << "sp1 use count: " << sp1.use_count() << std::endl;  // 输出 2std::cout << "sp2 use count: " << sp2.use_count() << std::endl;  // 输出 2return 0;
}

#include <iostream>
#include <thread>// 线程执行的函数
void threadFunction() {std::cout << "Hello from thread!" << std::endl;
}int main() {// 创建线程并执行std::thread t(threadFunction);// 等待线程完成t.join();return 0;
}

#include <iostream>
#include <thread>
#include <mutex>std::mutex mtx;  // 互斥量用于保护共享数据void print_message(const std::string& message) {std::lock_guard<std::mutex> lock(mtx);  // 自动加锁，作用域结束时自动解锁std::cout << message << std::endl;
}int main() {std::thread t1(print_message, "Hello from thread 1");std::thread t2(print_message, "Hello from thread 2");t1.join();t2.join();return 0;
}

#include <iostream>int main() {const char* raw_str = R"(Line 1
Line 2
Line 3)";std::cout << raw_str << std::endl;return 0;
}

#include <iostream>int main() {long long big_num = 9223372036854775807LL;unsigned long long ubig_num = 18446744073709551615ULL;std::cout << "Long long: " << big_num << std::endl;std::cout << "Unsigned long long: " << ubig_num << std::endl;return 0;
}

#include <iostream>void f(int) {std::cout << "Function with int parameter" << std::endl;
}void f(char*) {std::cout << "Function with char* parameter" << std::endl;
}int main() {f(0);        // 调用 f(int)f(nullptr);  // 调用 f(char*)return 0;
}

#include <iostream>// constexpr 函数必须简单，且能在编译时计算结果
constexpr int square(int x) {return x * x;
}int main() {constexpr int val = square(5);  // 在编译时计算出 val = 25int arr[val];  // 数组大小为 25std::cout << "Square of 5 is: " << val << std::endl;  // 输出 Square of 5 is: 25return 0;
}

#include <iostream>class Base {
public:virtual void show() const {std::cout << "Base show" << std::endl;}
};class Derived : public Base {
public:void show() const override {  // 确保是重写基类的方法std::cout << "Derived show" << std::endl;}void display() final {  // 防止进一步重写std::cout << "Derived display" << std::endl;}
};class FurtherDerived : public Derived {
public:// void display() override;  // 编译错误：不能重写 final 方法
};int main() {Base* b = new Derived();b->show();  // 调用 Derived 的 show 方法delete b;return 0;
}

#include <iostream>template<typename T, typename U>
auto add(T t, U u) -> decltype(t + u) {return t + u;
}int main() {std::cout << add(1, 2.5) << std::endl;  // 输出 3.5std::cout << add(std::string("Hello "), "World!") << std::endl;  // 输出 Hello World!return 0;
}

#include <iostream>int main() {int x = 10;decltype(x) y = x + 5;  // y 的类型是 intstd::cout << "y = " << y << std::endl;  // 输出 y = 15return 0;
}

#include <iostream>
#include <vector>// 使用 typedef 定义别名
typedef std::vector<int> IntVector;// 使用 using 定义别名
using IntList = std::vector<int>;int main() {IntVector vec = {1, 2, 3};IntList lst = {4, 5, 6};for (auto i : vec) {std::cout << i << " ";  // 输出 1 2 3}std::cout << std::endl;for (auto i : lst) {std::cout << i << " ";  // 输出 4 5 6}std::cout << std::endl;return 0;
}

#include <iostream>template<typename T>
void checkType() {static_assert(sizeof(T) == 4, "Type size must be 4 bytes");
}int main() {checkType<int>();  // 正确：int 通常是 4 字节// checkType<double>();  // 错误：double 通常不是 4 字节，编译期断言失败return 0;
}

#include <iostream>enum class Color { Red, Green, Blue };
enum class Fruit { Apple, Orange, Banana };int main() {Color color = Color::Red;Fruit fruit = Fruit::Apple;// 错误：不能隐式转换 enum class 类型// int colorValue = color;// 正确：显式转换为整数int colorValue = static_cast<int>(color);std::cout << "Color value: " << colorValue << std::endl;  // 输出 0return 0;
}

#include <iostream>void func() noexcept {std::cout << "This function is noexcept" << std::endl;
}int main() {func();return 0;
}