Cod sursa(job #902468)
Utilizator | Data | 1 martie 2013 14:26:35 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.35 kb |
#include <stdio.h>
using namespace std;
FILE *f=fopen("ciur.in","r"),
*g=fopen("ciur.out","w");
int n,i,j,nr;
char a[2000000];
int main()
{
fscanf(f,"%d",&n);
for(i=2;i<=n;i++){
if(a[i]==0){
nr++;
for(j=i;j<=n;j+=i)
a[j]=1;
}
}
fprintf(g,"%d",nr);
return 0;
}