Cod sursa(job #709989)
Utilizator | Data | 8 martie 2012 19:11:54 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 50 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.29 kb |
#include <fstream>
using namespace std;
char a[2000000];
int main()
{
ifstream f("ciur.in");
int n,i,o,rez;
f>>n;
rez=0;
f.close();
for(i=2;i<=n;i++)
{
if(a[i]==0)
rez++;
for(o=i;o<=n;o+=i)
a[o]=1;
}
ofstream g("ciur.out");
g<<rez;
g.close();
return 0;
}