Cod sursa(job #1126219)

Utilizator FasinedJohnny Bravo Fasined Data 26 februarie 2014 22:02:43
Problema Aria Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;
int n,i;
double s,x,y,x1,x2,y1,y2;

ifstream fin("aria.in");
ofstream fout("aria.out");

int main()
{
    fin>>n;
    fin>>x1>>y1;
    x=x1,y=y1;

    for(i=1;i<n;i++)
    {
        fin>>x2>>y2;
        s+=(x1*y2-x2*y1);
        x1=x2,y1=y2;
    }
    s+=x2*y-x*y2;

    fout<<s/2;
    return 0;
}