Both programs show the coordinate of mouse (x,y)

2. void draw()
3. {
4.  println("x: "+mouseX +"   "+"y: "+ mouseY);
5. }

Emily,
Thanks for this, but when I copy the first program using printIn, at the bottom I get "The function printIn(String) does not exist."

When I copy the second program using print, I do get continuous feedback at the bottom ... is this area called the console?

That's weird, both work for me, what version of Processing are you using?

"println" prints the string in the console (yes, that's the console) and start a new line (like hitting Enter after printing), while "print" just keeps putting the strings in sequence (it looks kinda messy for debugging).