Cod sursa(job #895921)
Utilizator | Domnita Dan tandura | Data | 27 februarie 2013 13:03:53 |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.52 kb |
#include <iostream>
#include <fstream>
using namespace std;
int n,nr;
bool x[2000001];
void citire()
{
ifstream f("ciur.in");
f>>n;
f.close();
}
void ciur()
{
for(int i=2;i<=n;i++)
if(x[i]==0)
for(int j=i+i;j<=n;j+=i)
x[j]=1;
for(int i=2;i<=n;i++)
if(x[i]==0)
nr++;
}
void afisare()
{
ofstream g("ciur.out");
g<<nr<<"\n";
g.close();
}
int main()
{
citire();
ciur();
afisare();
return 0;
}