Cod sursa(job #386203)
Utilizator | Data | 24 ianuarie 2010 12:39:35 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.3 kb |
#include<fstream>
using namespace std;
ifstream f("ciur.in");
ofstream g("ciur.out");
int c,n,i,j;
char prim[2000001];
int main()
{
f>>n;
for(i=2;i<=n;i++)
prim[i]=1;
for(i=2;i<=n;i++)
if(prim[i])
{for(j=i;j<=n;j=j+i)
prim[j]=0;
c++;}
g<<c;
f.close(); g.close();
return 0;
}