Mouse Interfacing In Turbo C++

I am trying to add interactive mouse interfacing to my program but I am not able to understand the need for delay() in it.

Here's the code:

do
{
    getmousepos(&button,&x,&y);
    if(button==1)
    {
        delay(500);
        xx[i] = x;
        yy[i] = y;
        i++;
    }
}while(!kbhit());

Not sure what delay() does here. Because if the button is pressed, the co-ordinates will get allocated to their respective arrays anyway. Then what is the need to add a delay?

The program with delay() gives proper output.
But if I remove it, nothing gets printed on screen.
What's so important about delay() in this case?

Turbo C++ ... that takes me back. Here is what I am expecting is happening and why that delay() is needed.

What you have here is a polling loop. Without the delay(), you are going to flood your xx[] and yy[] buffers when button is 1, and probably overflow them too. Remember, the computer can execute that loop a great many times while you have that mouse button pressed. The delay() evens that out somewhat.