#include<stdio.h>
main()
{
    int x,y,t;
    printf("enter x&y:\n");
        scanf("x=%d y=%d\n",x,y);
        t=x;x=y;y=t;
        printf("x=%d y=%d\n",x,y);

}

很好奇你是怎么输入的?~

scanf("x=%d y=%d\n",x,y);x y最起码也该取个地址呀。这种写法是一种自寻烦恼的写法，规规矩矩按正规写法就行
scanf("%d%d",&x,&y);
或者
printf("key into x y :  ");
scanf("%d%d",&x,&y);

楼上正解