Cod sursa(job #2484435)

Utilizator Horea_Mihai_SilaghiHorea Mihai Silaghi Horea_Mihai_Silaghi Data 31 octombrie 2019 09:16:47
Problema Aria Scor 10
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.35 kb
Raporteaza aceasta sursa 
#include <fstream>

using namespace std;
ifstream cin("aria.in");
ofstream cout("aria.out");
int n;
double s=0,a,b,x,y,a1,b1;
int main()
{
    cin>>n;
    cin>>x>>y;
    a1=x;
    b1=y;
    for(int i=1;i<n;i++)
    {
        cin>>a>>b;
        s=s+x*b-y*a;
        x=a;
        y=b;
    }
    s=s+x*b1-y*a1;
    cout<<s/2;
    return 0;
}