Cod sursa(job #948533)
Utilizator | Data | 10 mai 2013 20:24:03 | |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include <fstream>
#include <iomanip>
using namespace std;
ifstream f("aria.in"); ofstream g("aria.out");
int n,i;
double Arie = 0.0;
struct p{double x, y;} P[100004];
int main()
{ f>>n;
for(i=1;i<=n;++i) f>>P[i].x>>P[i].y;
P[n+1]=P[1];
for(i=1;i<=n;++i) Arie+=(P[i].x*P[i+1].y-P[i+1].x*P[i].y);
Arie/=2.0;
if(Arie<0) Arie=-Arie;
g<<fixed<<setprecision(5)<<Arie<<'\n';
return 0;
}