Cod sursa(job #540214)

Utilizator bhaskruMarius 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
Raporteaza aceasta sursa 
#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;
}