Cod sursa(job #2317192)
Utilizator | Hantig Lorena LorenaMaria | Data | 12 ianuarie 2019 22:08:11 |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include <fstream>
#include <iomanip>
using namespace std;
ifstream in("aria.in");
ofstream out("aria.out");
int n;
long double r;
struct point
{ double x,y;
}p[100002];
int main()
{ in>>n;
for(int i=1;i<=n;i++)
in>>p[i].x>>p[i].y;
p[n+1]=p[1];
for(int i=1;i<=n;i++)
r+=p[i].x*p[i+1].y-p[i+1].x*p[i].y;
r/=2.0;
out<<setprecision(6)<<fixed<<r;
in.close();
out.close();
return 0;
}