杭电 2056 Rectangles

#include<stdio.h>
void swap(double *x,double *y){
double t;
t = *x;
*x = *y;
*y = t;
}

int main()
{
double x1,x2,x3,x4,y1,y2,y3,y4,x5,y5,x6,y6;
while(scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4) != EOF)//必须有l
{
if(x1>x2)swap(&x1,&x2);
if(y1>y2)swap(&y1,&y2);
if(x3>x4)swap(&x3,&x4);
if(y3>y4)swap(&y3,&y4);
x5 = x1>x3?x1:x3;
y5 = y1>y3?y1:y3;
x6 = x2>x4?x4:x2;
y6 = y2>y4?y4:y2;
//printf("%.2lf\n",x6 >= x5 && y6 >= y5?(x6-x5)*(y6-y5):0);
if(x6 > x5 && y6 > y5) printf("%.2f\n",(x6-x5)*(y6-y5));
else printf("0.00\n");
}
return 0;
}