Cod sursa(job #550180)
Utilizator | Data | 9 martie 2011 12:01:00 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.28 kb |
#include<fstream.h>
#include<math.h>
int main()
{
ifstream fin("ciur.in");
ofstream fout("ciur.out");
long long n,i,d,s=1,p,x;
fin>>n;
for(i=3;i<=n;i++)
{
x=sqrt(i);
p=0;
for(d=2;d<=x&&p==0;d++)
if(i%d==0) p++;
if(p==0) s++;
}
fout<<s;
return 0;
}