Cod sursa(job #540214)
| Utilizator |  Marius S bhaskru |
Data | 23 februarie 2011 20:00:46 |
|---|---|---|---|
| Problema | Ciurul lui Eratosthenes | Scor | 100 |
| Compilator | cpp | Status | done |
| Runda | Arhiva educationala | Marime | 0.34 kb |
#include<iostream.h>
#include<fstream.h>
fstream f,g;
char prim[2000005];
int n,ne;
int main()
{
f.open("ciur.in",ios::in);
g.open("ciur.out",ios::out);
f>>n;
ne=0;
for(int i=2;i<=n;i++)
prim[i]=1;
for(int i=2;i<=n;i++)
if(prim[i]!=0)
{ne++;
for(int j=i+i;j<=n;j+=i)
prim[j]=0;
}
g<<ne;
f.close();
g.close();
return 0;
}