http://www.jackxiang.com/index.php zh-cn http://www.jackxiang.com/post// jack <xdy108@126.com> Tue, 09 Sep 2008 08:26:12 +0000 http://www.jackxiang.com/post//
#include <stdio.h>

int main() {
    int i,j;

    printf("please input two numbers:\n");
    scanf("%d %d",&i,&j);

    printf("the first number i is: %d \n",i);
    printf("the second number j is: %d \n",j);
  
  
    asm ("pushl %%eax\n\t"
         "pushl %%ebx\n\t"
         "popl  %%eax\n\t"
         "popl  %%ebx"
         :"=a"(i),"=b"(j)
         :"a"(i), "b"(j));
  
  
    printf("after swap \n");
    printf("the first number i is: %d \n",i);
    printf("the first number j is: %d \n",j);
  
}


用异或：（RAID里面就用到了这技术。三个里面知道任意两个就可以恢复第三个）


    #define swap(a, b) (a) ^= (b), (b) ^= (a), (a) ^= (b)

    #include <stdio.h>

    int main(void)
    {
        int ival1 = 10, ival2 = 20;

        printf("%d %d\n", ival1, ival2);
        swap(ival1, ival2);
        printf("%d %d\n", ival1, ival2);
    }



]]> http://www.jackxiang.com/post//#blogcomment <user@domain.com> Thu, 01 Jan 1970 00:00:00 +0000 http://www.jackxiang.com/post//#blogcomment