Cod sursa(job #326624)

Utilizator cosmyoPaunel Cosmin cosmyo Data 25 iunie 2009 18:22:29
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include<fstream.h>
int x[2000001];
int main()
{long j,i,n,nr;
 ifstream fin("ciur.in");
  fin>>n;
   for(i=2;i<=n;i++)
	   x[i]=1;
   for(i=2;i<=n;i++)
    if(x[i])
     for(j=i+i;j<=n;j+=i)
		x[j]=0;
 fin.close();
 ofstream fout("ciur.out");
 nr=0;
  for(i=2;i<=n;i++)
	  if(x[i])
		nr++;
 fout<<nr;
 fout.close();
return 0;
}