交换变量的方法

法一，直接上代码

#include <stdio.h>
int main(int argc, const char * argv[]) {
    int a = 1,b = 2,temp = 3;
    printf("交换前:%d %d\n",a,b);
    temp = a;
    a = b;
    b= temp;
    printf("交换后:%d %d\n",a,b);
    return 0;
}

法二：

#include <stdio.h>

void swap（int *p，int *q）{
    
    int temp;
    temp = *p;
    *p = *q;
    *q = temp;
}


int main(int argc, const char * argv[]) {
    int a = 1,b = 2;
    printf("交换前:%d %d\n",a,b);
    swap(&a,&b);
    printf("交换后:%d %d\n",a,b);
    return 0;
}

法三：

#include <stdio.h>
int main(int argc, const char * argv[]) {
    int a = 1,b = 2;
    printf("交换前:%d %d\n",a,b);
    a = a + b;
    b = a - b;
    a = a - b;
    printf("交换后:%d %d\n",a,b);
    return 0;
}

法四：

#include <stdio.h>
int main(int argc, const char * argv[]) {
    int a=1,b=2;
    a = a^b;
    b = a^b;
    a = a^b;
    printf("%d %d",a,b);
    return 0;
}

啊哈，解释一下这个原理咯！

a  == 00000000000000000000000000000001，

b  == 00000000000000000000000000000010，

如下：

00000000000000000000000000000001    a == 1

00000000000000000000000000000010    b == 2

______________________________________

00000000000000000000000000000011     a == 3

00000000000000000000000000000010    b == 2

______________________________________

00000000000000000000000000000001    b == 1

00000000000000000000000000000011    a == 3

______________________________________

00000000000000000000000000000010   a == 2

总结，小学的知识，有一天看见了，觉得有意思，分享一下！

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转载于:https://my.oschina.net/u/2293850/blog/753487