Cod sursa(job #588356)
Utilizator | Data | 7 mai 2011 19:01:28 | |
---|---|---|---|
Problema | Ciurul lui Eratosthenes | Scor | 30 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.33 kb |
#include<fstream>
using namespace std;
int i,n,a[2000001];
unsigned long nr=0;
unsigned long ciur()
{
int i,j;
for(i=2;i<=n;i++)
{
if(!a[i])
{
nr++;
for(j=i+i;j<=n;j+=i)
a[j]=1;
}
}
return nr;
}
int main()
{
ifstream f("ciur.in");
ofstream g("ciur.out");
f>>n;
g<<ciur();
return 0;
}