Cod sursa(job #291618)
Utilizator | Data | 30 martie 2009 08:45:56 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 100 |
Compilator | cpp | Status | done |
Runda | The Beginners | Marime | 0.35 kb |
#include<fstream.h>
int main()
{char prim[2000001];
long nr=0,i,j,n;
ifstream f("ciur.in");
ofstream g("ciur.out");
f>>n;
for(i=1;i<=n;i++)
prim[i]=1;
prim[1]=0;
for(i=2;i<=n;i++)
if(prim[i])
for(j=i+i;j<=n;j+=i)
prim[j]=0;
for(i=1;i<=n;i++)
if(prim[i])nr++;
g<<nr;
return 0;
}