Cod sursa(job #877156)
Utilizator | Data | 12 februarie 2013 17:10:25 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.41 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int n , c;
char a[20000000];
int main()
{
int i, j;
fin>>n;
for(i=2; i<=n; i++)
if (!a[i])
{
c++;
for (j = i+i; j<=n; j+=i)
a[j]=1;
}
fout<<c;
fin.close();
fout.close();
return 0;
}