交换两个变量的值

#include <stdio.h>

int main(int argc, const char * argv[]) {
    
    //第一种方式，开发中常用
    int a = 10;
    int b = 20;
    int temp;//空瓶子
    temp = a;
    a = b;
    b = temp;
    printf("a = %d,b = %d\n",a,b);
    
    return 0;
}

#include <stdio.h>

int main(int argc, const char * argv[]) {
    
    //第二种方式
    int a = 10;
    int b = 20;
    
    a = b - a;//20 - 10   a = 10
    b = b - a;//20 - 10   b = 10
    a = b + a;//10 + 10   a = 20
    printf("a = %d,b = %d\n",a,b);
    
    return 0;
}

#include <stdio.h>
int main(int argc, const char * argv[]) {
    
    //第三种方式
    int a = 10;
    int b = 20;
    a = a ^ b; //a = 10 ^ 20;
    b = a ^ b; //b = 10 ^ 20 ^ 20; b = 10
    a = a ^ b; //a = 10 ^ 20 ^ 10; a = 20
    printf("a = %d,b = %d\n",a,b);

    return 0;
}