#include<stdio.h>
int main(){int t,a,b,c,d;printf("请输入四个数：");scanf("%d %d %d %d",&a,&b,&c,&d);printf("a=%d,b=%d,c=%d,d=%d\n",a,b,c,d);if(a>b){t=a;a=b;b=t;}if(a>c){t=a;a=c;c=t;}if(a>d){t=a;a=d;d=t;}if(b>c){t=b;b=c;c=t;}if(b>d){t=b;b=d;d=t;}if(c>d){t=c;c=d;d=t;}printf("排序结果如下：");printf("%d  %d  %d  %d ",a,b,c,d);return 0;	}

重要代码是：
a>b

t=a;
a=b;
b=t