Cod sursa(job #218721)

Utilizator alex_aurelia_31Neamtu Alexandra alex_aurelia_31 Data 3 noiembrie 2008 11:53:36
Problema Ciurul lui Eratosthenes Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.31 kb
Raporteaza aceasta sursa 
#include<stdio.h>
unsigned long int n,a[20000000],nr;

int main()
{
FILE *f,*g;
f=fopen("ciur.in","r");
g=fopen("ciur.out","w");

fscanf(f,"%d",&n);
int i,j;
for(i=2;i<=n;i++)
a[i]=1;
for(i=2;i<=n/2;i++)
for(j=i;j<=n/i;j++)
a[i*j]=0;
for(i=2;i<=n;i++)
if(a[i])
nr++;
fprintf(g,"%d",nr);
return 0;
}