Cod sursa(job #673818)
Utilizator | cius catalin ciuscatalin | Data | 4 februarie 2012 22:07:30 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.4 kb |
#include <fstream>
using namespace std;
int main()
{
int i,nr=0,n,j;
char ciur[2000001];
ifstream cin("ciur.in");
ofstream cout("ciur.out");
cin>>n;
for(i=2; i<=n; i++)
{
if (ciur[i]==0)
{
nr ++;
for (j=i+i;j<=n;j=j+i)
ciur[j]=1;
}
}
cout<<nr;
cin.close();
cout.close();
return 0;
}