Cod sursa(job #1001456)
Utilizator | Cosma Cristian Alexandru alexx.cosma | Data | 24 septembrie 2013 23:26:28 |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.59 kb |
#include <iostream>
#include <fstream>
#include <cmath>
#include <iomanip>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
const int nmax = 100005;
struct point{
double x;
double y;
};
point vec[nmax];
int main()
{
int n;
fin >>n;
for(int i=0;i<n;i++){
fin >> vec[i].x;
fin >> vec[i].y;
}
vec[n] = vec[0];
double aria=0;
for(int i=0;i<n;i++){
aria+=(vec[i].x*vec[i+1].y - vec[i+1].x*vec[i].y);
}
fout << fixed << setprecision(5) << fabs(aria/2.0);
return 0;
}