Cod sursa(job #291031)
Utilizator | Data | 29 martie 2009 11:52:51 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.38 kb |
#include<fstream.h>
ifstream fin("ciur.in");
ofstream fout("ciur.out");
int main()
{
char ciur[2000001];
int n,i,j;
memset(ciur,'1',sizeof(ciur));
fin>>n;
fin.close();
int gasite=0;
for(i=2;i<=n;i++)
if(ciur[i]=='1')
{gasite++;
for(j=2;j*i<=n;j++)
ciur[i*j]='0';}
fout<<gasite;
fout.close();
return 0;}