Cod sursa(job #441861)
Utilizator | Data | 13 aprilie 2010 16:28:04 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 90 |
Compilator | c | Status | done |
Runda | Arhiva educationala | Marime | 0.33 kb |
#include <stdio.h>
int main (){
int i,j,n,ok;;
char v[2000002];
FILE *f,*g;
f=fopen("ciur.in","r");
g=fopen("ciur.out","w");
fscanf(f,"%d",&n);
for(i=2;i<n/2;i++)
if(v[i]==0)
{
for(j=i;j<=n;j+=i)
v[j]=1;
ok++;
}
for(i=n/2;i<=n;i++)
if(v[i]==0)
ok++;
fprintf(g,"%d",ok);
fclose(f);
fclose(g);
return 0;
}