C++ Program for getting HCF

#include<iostream>
using namespace std;

int main()
{
const int N=3;
int numbers[N],HCF;
int i,small;
cout << "Enter nmbers:\n";
for( i=0 ; i<N ; i++ )
{
do
{
cout << "Enter number "
<< (i+1)
<< ": ";
cin >> numbers[i];}while(numbers[i]<=0);
}
small=numbers[0];
for( i=1 ; i<N ; i++ )
{
if( numbers[i]<small )
small=numbers[i];
}
int index;
for( i=small ; i>=0 ; i-- )
{
index=-1;
for( int j=0 ; j<N ; j++ )
{
if( numbers[j]%i!= 0 )
{
index=i;
break;
}
}
if( index==-1 )
{
HCF=i;
break;
}
/*if( numbers[0]%i==0 && numbers[1]%i==0 && numbers[2]%i==0 )
{
HCF=i;
break;
}
}
cout << "\nHCF is: "
<< HCF
<< endl;

return 0;
}