Cod sursa(job #287347)

Utilizator LuffyBanu Lavinia Luffy Data 24 martie 2009 19:26:19
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;
char a[2000000];
int main()
{unsigned long n,i,j;
int num=0;
  ifstream f("ciur.in");
  ofstream g("ciur.out");
f>>n;
  for(i=2;i*i<=n;i++)
   if(a[i]==0)
    for(j=2;i*j<=n;j++)
	 a[i*j]=1;
	 
  for(i=2;i<=n;i++)
    if(a[i]==0) num++;
g<<num<<'\n';
f.close();
g.close();
return 0;
}