Cod sursa(job #1807450)
Utilizator | Patras Sanda sanda-maria | Data | 16 noiembrie 2016 16:53:50 |
---|---|---|---|
Problema | Aria | Scor | 10 |
Compilator | c | Status | done |
Runda | Arhiva educationala | Marime | 0.54 kb |
#include <stdio.h>
#include <stdlib.h>
float xi,yi,x1,y1,x2,y2,N,A;
int i;
int main()
{
FILE *Fin,*Fout;
Fin=fopen("aria.in","r");
Fout=fopen("aria.out","w");
fscanf(Fin,"%f",&N);
fscanf(Fin,"%f",&xi);
fscanf(Fin,"%f",&yi);
x1=xi;
y1=yi;
for(i=1;i<N;i++)
{
fscanf(Fin,"%f",&x2);
fscanf(Fin,"%f",&y2);
A=A+x1*y2-x2*y1;
x1=x2;
y1=y2;
}
A=fabs((A+x1*yi-xi*y1)/2);
fprintf(Fout,"%.5f",A);
fclose(Fin);
fclose(Fout);
return 0;
}