Cod sursa(job #649842)
Utilizator | Data | 16 decembrie 2011 20:26:07 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | c | Status | done |
Runda | Arhiva educationala | Marime | 0.33 kb |
#include<stdio.h>
int v[2000005];
int i,j,n,k;
int main()
{FILE *fin,*fout;
fin=fopen("ciur.in","r");
fout=fopen("ciur.out","w");
fscanf(fin,"%d",&n);
v[1]=1;
k=1;
for(i=3;i<=n;i=i+2)
if(v[i]==0)
{k++;
for(j=3*i;j<=n;j=j+2*i)
v[j]=1;
}
fprintf(fout,"%d",k);
fclose(fin);
fclose(fout);
return 0;
}