Cod sursa(job #355309)
Utilizator | Data | 10 octombrie 2009 18:25:49 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.35 kb |
#include<iostream.h>
int i,j,n,cn;
bool ok;
int main()
{
freopen("ciur.in","r",stdin);
freopen("ciur.out","w",stdout);
cin>>n;
cn=0;
for(i=2;i<=n;++i)
{
if(i==2) cn++;
if(i%2==1)
{
ok=1;
for(j=2;j*j<=i;++j)
{
if(i%j==0)
{
ok=0;
break;
}
}
if(ok) cn++;
}
}
cout<<cn;
return 0;
}