Cod sursa(job #943431)
Utilizator | Rares Cheseli rares96cheseli | Data | 25 aprilie 2013 14:09:47 |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include <fstream>
#include <cmath>
#include <iomanip>
using namespace std;
ifstream f("aria.in");
ofstream g("aria.out");
long double x[100005],y[100005],arie=0.0;
int n;
int main()
{
f>>n;
for (int i=1; i<=n; i++) f>>x[i]>>y[i];
x[n+1]=x[1]; y[n+1]=y[1];
for (int i=1; i<=n; i++) arie+=(x[i]*y[i+1]-y[i]*x[i+1]);
arie*=0.5;
g<<fixed<<setprecision(5)<<fabs(arie)<<'\n';
}