Diamond With 3 Do While Loops

Code:

// http://welearncpp.blogspot.com
#include<iostream>
using namespace std;

void main()
{
 int row,space,star=1;
 cout << "Enter an odd number :";
 cin >> row;
 if((row%2)==0)
 row--;
 space=row;
 int a=1;
 do
 {
  int b=1;
  do
  {
   cout << " ";
   b++;
  } while(b<=space);

  int c=1;
  do
  {
   cout << "*";
   c++;
  } while (c<=star);
  if(a<=row/2)
  {
   space--;
   star+=2;
  }
  else
  {
   space++;
   star-=2;
  }
  cout<<endl;
  a++;
 } while(a<=row);
}