Cod sursa(job #1735622)
Utilizator | Data | 30 iulie 2016 14:36:24 | |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.53 kb |
#include <iostream>
#include <fstream>
#include <iomanip>
#include <cmath>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
#define nmax 100003
struct p{double x,y ;};
p v[nmax];
long double aria;
int main()
{
int n,i;
fin>>n;
for(i=1; i<=n; i++)
fin>>v[i].x>>v[i].y;
v[n+1]=v[1];
for(i=1; i<=n; i++)
aria+=(v[i].x*v[i+1].y - v[i].y*v[i+1].x);
fout<<setprecision(5)<<fixed<<abs(aria/2.0);
fin.close();
fout.close();
return 0;
}