#include void swap(double *a,double *b){double t; t=*a;*a=*b;*b=t;}int main(){double a,b,*p1=&a,*p2=&b;scanf("%lf%lf",&a,&b);printf("a=%lg\tb=%lg\n",a,b);swap(p1,p2);printf("交换后:\na=%lg\tb=%lg\n",a,b);return 0;}