Cod sursa(job #925504)
Utilizator | Tudor Siminic tudors | Data | 24 martie 2013 16:30:45 |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.5 kb |
#include <cmath>
#include <stdio.h>
#define N 100005
using namespace std;
typedef struct {double x,y;} PUNCT;
int n,i;
double rez=0;
PUNCT A[N];
FILE *f,*g;
int main()
{
f=fopen("aria.in","r");
g=fopen("aria.out","w");
fscanf(f,"%d",&n);
for (i=0;i<n;++i)
fscanf(f,"%lf %lf",&A[i].x,&A[i].y);
A[n]=A[0];
for (i=0;i<n;++i)
rez=rez+(A[i].x*A[i+1].y-A[i+1].x*A[i].y);
fprintf(g,"%lf",(rez/2));
fclose(f);
fclose(g);
return 0;
}