Cod sursa(job #2205110)
Utilizator | Tepes Alexandru Eclipse | Data | 17 mai 2018 23:04:36 |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.56 kb |
#include <iostream>
#include <fstream>
#include <iomanip>
#define dMAX 100000
using namespace std;
int n, t;
struct Point{
double x, y;
} arr[dMAX + 2];
double A, z = 2;
ifstream fin("aria.in");
ofstream fout("aria.out");
int main()
{
int i, j;
fin >> n;
for (i = 0; i < n; i++) {
fin >> arr[i].x >> arr[i].y;
}
t = n;
for (i = 0; i < n; i++) {
A = A + (arr[i].x * (arr[(i + 1) % t].y) - arr[(i + 1) % t].x * arr[i].y);
}
fout << setprecision(6) << fixed << A / z;
return 0;
}