C++ recursive function (very simple one)... [help needed!]

[codeyy]

How do I write a recursive function in C++ to display a triangle of * like this using a parameter size (e.g. 4 in the following example):

*
**
***
****

I am able to write a recursive function to display an inverted triangle like this:

****
***
**
*

The code for the inverted triangle function is:

void inverted(int a)
{
	if (a==1)
	{
		cout<<"*"<<endl;
	}
	else
	{
		for (int i=0; i<a; i++)
		{
			cout<<"*";
		}
		cout<<endl;
		inverted(a-1);
	}
}

I am allowed to use a loop (e.g. for loop) to print a row of * but I must use a recursive function to control the number of rows.

Please, provide some insight into the problem. I need it to work urgently but I am not able to figure out a solution.