交换两个变量常规四种做法

#include <stdio.h>

void swap1(int a,int b)
{
    a = a ^ b;
    b = a ^ b;
    a = a ^ b; //a^b^a
    printf("%d,%d\n",a,b);
}

void swap2(int a,int b)
{
    a = a + b;
    b = a - b;
    a = a - b;
    printf("%d,%d\n",a,b);
}

void swap3(int a,int b)
{
    int t = a;
    a = b;
    b = t;
    printf("%d,%d\n",a,b);
}

void swap4(int a,int b)
{
    a = a * b;
    b = a / b;
    a = a / b;
    printf("%d,%d\n",a,b);
}

int main () {
    int a = 3;
    int b = 4;
    swap1(a,b);
    swap2(a,b);
    swap3(a,b);
    swap4(a,b);
    return 0;
}

这四类在面试过程中常被问到，希望大家掌握一下。