Cod sursa(job #588362)

Utilizator lily3Moldovan Liliana lily3 Data 7 mai 2011 19:09:44
Problema Ciurul lui Eratosthenes Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.36 kb
Raporteaza aceasta sursa 
#include<fstream>
using namespace std;

unsigned long i,n,nr=0;
char a[2000001];
int ciur()
{
	int i,j;
	for(i=2;i<=n;i++)
	{
		if(a[i]=='0')
		{
			nr++;
			for(j=i+i;j<=n;j+=i)
				a[j]='1';
		}
	}
	return nr;
}
int main()
{
	ifstream f("ciur.in");
	ofstream g("ciur.out");
	f>>n;
	for(i=0;i<=n;i++)
		a[i]='0';
	g<<ciur();
		return 0;
}