Cod sursa(job #280734)
Utilizator | Data | 13 martie 2009 15:42:07 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.34 kb |
#include<fstream>
#include<math.h>
using namespace std;
int main (){
int i,j,ok,ct;
unsigned long int n;
ifstream f("ciur.in");
ofstream g("ciur.out");
f>>n;
ct=0;
for(i=2;i<=n;i++){
ok=1;
for(j=2;j<=sqrt(1.0*i);j++){
if(i%j==0)
ok=0;
}
if(ok==1)
ct++;
}
g<<ct;
f.close();
g.close();
return 0;
}