Cod sursa(job #523630)
Utilizator | Data | 18 ianuarie 2011 18:15:05 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.25 kb |
#include<fstream.h>
ifstream f("ciur.in");ofstream g("ciur.out");
int x,i,j,np;
char prim[2000001];
int main()
{f>>x;
for(i=2;i<=x;i++)
if(!prim[i])
{
np++;
for(j=i+i;j<=x;j+=i) prim[j]=1;
}
g<<np;
g.close();
return 0;
}