UVa 10242 Fourth Point!! Solution

#include<stdio.h>
int main()
{
double a1,a2,b1,b2,c1,c2,d1,d2,e1,e2;
while(scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&a1,&a2,&b1,&b2,&c1,&c2,&d1,&d2)==8)
{
if(a1==b1 && a2==b2)
{e1=c1+d1-a1;
e2=c2+d2-a2;}
else if(a1==c1 && a2==c2)
{e1=b1+d1-a1;
e2=b2+d2-a2;}
else if(a1==d1 && a2==d2)
{e1=c1+b1-a1;
e2=c2+b2-a2;}
else if(b1==c1 && b2==c2)
{e1=a1+d1-b1;
e2=a2+d2-b2;}
else if(b1==d1 && b2==d2)
{e1=a1+c1-b1;
e2=a2+c2-b2;}
else if(c1==d1 && c2==d2)
{e1=b1+a1-c1;
e2=b2+a2-c2;}
printf("%.3lf %.3lf\n",e1,e2);
}
return 0;
}