Cod sursa(job #1494879)
Utilizator | Data | 1 octombrie 2015 22:34:15 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | pregatire_cl.10_cnpr | Marime | 0.42 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int d;
int prim(int x)
{
if(x==2)
return 1;
if(x%2==0)
return 0;
for(d=3;d<=((double)sqrt(x));d++)
if(x%d==0)
return 0;
return 1;
}
int main()
{
int i,n,k=0;
f>>n;
for(i=n;i>1;i--)
if(prim(i))
k++;
g<<k;
return 0;
}