Cod sursa(job #275498)

Utilizator raulkeleRaul Kele Cristian raulkele Data 10 martie 2009 15:09:31
Problema Ciurul lui Eratosthenes Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include<stdio.h>
long int n,np;
long int i,j;
int main()
{
char p[2000001];
FILE *in=fopen("ciur.in","r");
FILE *out=fopen("ciur.out","w");
fscanf(in,"%ld",&n);
np=1;
for(i=0;i<=n;i++)
p[i]=0;
for(i=3;i<=n;i=i+2)
{
 if(p[i]==0)
 {
	np++;
	for(j=i*i;j<=n;j=j+i)
	p[j]=1;
 }
}
fprintf(out,"%ld",np);
return 0;
}