Cod sursa(job #907859)
Utilizator | Data | 8 martie 2013 13:42:19 | |
---|---|---|---|
Problema | Aria | Scor | 10 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.37 kb |
#include<stdio.h>
struct point
{
float x,y;
}p,d;
int n;
float Aria;
int main()
{
freopen("aria.in","r",stdin);
freopen("aria.out","w",stdout);
scanf("%d%f%f",&n,&p.x,&p.y);
point first=p;
for(int i=1;i<n;i++)
{
scanf("%f%f",&d.x,&d.y);
Aria+=((p.x*d.y)-(d.x*p.y));
p=d;
}
Aria+=((p.x*first.y)-(first.x*p.y));
printf("%.4f",Aria/2);
}