CS Fundamentals: Debugging with the Step Button

All computer scientists, no matter how
experienced they are, run into errors or

something they need to fix.

This is where debugging comes in. Debugging is just a

word that means finding and fixing errors in
a program and the first step towards fixing

errors is to find them. Most puzzles have
a step button below the play space that

you can use to hunt for problems. If your
program doesn't work, press the "step"

button, and see what happens. Does the
character take action in the right way?

If everything looks good with the first
block of code, press the step button

again. How does everything look? Is it
still running right? Keep going through

your code, line by line, until you find
the first place where things go wrong.

What happened? What was supposed to
happen?

What does that tell you? In this puzzle I get
to the last line of code and don't reach

the goal. What happened? I got to the end
of my code without solving the puzzle.

What was supposed to happen?
I need to go forward one more step.

What does that tell me? It tells me I need to drag
out one more of these blocks and attach

it to the end, before I click run. Tada! That's how you debug a program.