[Lang] 运算符重载

合集 - Cpp开发(37)

1.[Lang] 静态变量2024-08-112.[Lang] Lambda表达式2024-08-113.[Lang] 类成员修饰符2024-08-124.[Lang] 构造与析构2024-08-135.[Lang] 智能指针2024-08-13

6.[Lang] 运算符重载2024-08-15

7.[Lang] 虚函数2024-08-168.[Lang] 函数模板2024-08-189.[Lang] 类模板2024-12-0110.二分查找2024-12-0211.链表操作2024-12-0312.栈和队列2024-12-0513.二叉树遍历2024-12-0614.归并分治2024-12-0615.快速排序2024-12-0716.堆结构2024-12-0817.位运算2024-12-0918.链表操作22024-12-1319.二叉树常见题目2024-12-1420.前缀树2024-12-2021.前缀和2024-12-2022.二叉树常见题目22024-12-1523.二维差分2024-12-2224.滑动窗口2024-12-2225.双指针2024-12-2826.二分答案法2024-12-2827.单调栈2024-12-2828.单调队列01-0629.并查集01-0630.洪水填充01-0631.一维动态规划01-0732.二维动态规划01-0733.二维动态规划201-0834.三维动态规划01-1035.子数组最大累加和01-1036.子数组最大累加和201-1337.零一背包01-15

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[Lang] 运算符重载

#include<iostream>
using namespace std;

class MyInt {
    friend ostream &operator<<(ostream &os, const MyInt &myint);
    friend istream &operator>>(istream &is, MyInt &myint);
private:
    int val;
public:
    MyInt() : val(0) {}
    MyInt(int val) : val(val) {}
    MyInt &operator++() {
        val++;
        return *this;
    }
    MyInt operator++(int) {
        MyInt temp = *this;
        val++;
        return temp;
    }
};

ostream &operator<<(ostream &os, const MyInt &myint) {
    os << myint.val;
    return os;
}
istream &operator>>(istream &is, MyInt &myint) {
    is >> myint.val;
    return is;
}

int main() {
    MyInt a, b;
    cin >> a >> b;
    cout << ++(++a) << endl;
    cout << (b++)++ << endl;
    return 0;
}

PS D:\CppDev\Lang\overload> cd "d:\CppDev\Lang\overload\" ; if ($?) { g++ test1.cpp -o test1 } ; if ($?) { .\test1 }
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1. 递增运算符

(1) 前置递增

• 返回值必须为引用，否则++(++a)后a的值将与预期不一致

(2) 后置递增

• 返回值不能为引用，否则将导致悬空指针问题

• 占位符int表示后置单目运算符，用于实现函数重载

2. 移位运算符

• 必须由普通函数重载，否则顺序将与预期不一致
• 必须返回标准输出流或标准输入流自身，否则将无法实现级联
• 由于是类外函数，必须在类内声明友元