swap的方法书写

#include <iostream>using namespace std;int swap1(int& x, int& y){    x += y;    y = x - y;    x = x - y;}int swap2(int& x, int& y){    x ^= y;    y ^= x;    x ^= y;}int main(){    int x = 1, y = 2;    swap1(x, y); // x = 2, y = 1;    swap2(x, y); // x = 1, y = 2;    return 0;}