Cod sursa(job #942698)
Utilizator | Johnny Depp Johny_Depp22 | Data | 23 aprilie 2013 11:57:10 |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include <fstream>
using namespace std;
ifstream f("aria.in");
ofstream g("aria.out");
int n,x[100005],y[100005];
long double arie=0.0;
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]+x[i+1]*y[i]);
arie/=2.0;
f<<fixed<<setprecision(5)<<fabs(arie)<<'/n';
f.close(); g.close();
return 0;
}