Cod sursa(job #284187)
Utilizator | Data | 21 martie 2009 10:15:59 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.53 kb |
#include<fstream.h>
#include<math.h>
unsigned long n,c,i;
unsigned int d,ok;
int prim(int);
int main()
{
ifstream In("ciur.in");
ofstream Out("ciur.out");
In>>n;
In.close();
for(i=1;i<=n;i++)
{
if( (i%2) || (i%3) ) continue;
else if(prim(i)) c++;
}
Out<<c<<'\n';
Out.close();
return 0;
}
int prim(int x)
{
ok=1;
for(d=2;d<=sqrt(n);d++)
{
if(x%d==0) {ok=0;break;}
}
return ok;
}