C++ programme Increasing digit pattern

//This programme is tested on visual studio 2012//
#include<iostream>
using namespace std;
void main()
{
int num, counter=1,sum=1,c=2;
cout<<"------------------------------------------------------------------------------\n";
cout<<"This programme will print a specific increasing pattern on entering number greater than 0\n";
cout<<"------------------------------------------------------------------------------\n";
   do
{

    cout<<"Enter num";
    cin>>num;
}
    while(num<=0);

    for(int i=1;i<=num;i++)
    {
      cout<<sum<<" ";
       c=2;
        for(int j=1;j<i;j++)
      {
       cout<<c<<" ";
       c=c+1;
        }
        cout<<endl;
      }
    cout<<"------------------------------------------------------------------------------\n";
    cout<<"Thank You for using.\nVisit http://bilalzahid22.blogspot.com/ for more\n";
    cout<<"------------------------------------------------------------------------------\n";
}