Run and walk through code
Your loop gives 45 and it should give 55. Ask DuckyHelper why, and it runs your code against tests, each one ticking in or showing expected against what it got. Then it plays your code back one step at a time, every variable as it changes, until you see it: the loop stopped one short. You fix it, and both tests pass.
Expected, and what it got.
Say run my code against these tests, or why does my loop give 45, not 55? Ducky runs it against tests. Each one ticks in green or opens to show what was expected and what your code returned, so you know exactly which case breaks.
Your code runs in a sandbox with no internet, so nothing it does can reach your files or the web.
On a Mac, ask about the code on your screen, in VS Code, a coding site or a notebook. In Eddy, paste it or ask Eddy to write the starting code with you.
Watch it run, one line at a time.
Ask show me what this loop does and a player opens: the line that runs next is highlighted, and every variable, array and pointer is drawn as it changes. Play it, pause it, drag to any step. Watching total climb and i stop at 9 tells you more than any explanation.
A Code window on Eddy's desk.
In Eddy, code opens in a Code window on the desk that runs: add_up, one line at a time, with the variables beside it and the output below. It is in the Mac app's Eddy tab.
Walk me through writing this.
On a Mac, ask Ducky to walk you through writing a piece of code. It says what the next line does, then ghosts that small chunk at your cursor in your own editor. Type it, and the next step follows. You end up with code you wrote, one chunk at a time.
Run it. Watch it. Fix it.
How a code lesson goes.
- 1. Ask why it is wrong
Press fn on your editor, or paste it into Eddy.
- 2. Run the tests
Each one passes, or shows expected against got.
- 3. Step through
Watch the variables until you see it.
- 4. Fix it yourself
Run again until every test passes.
See it run, then fix it.
Seeing a program run one step at a time makes the invisible part of code, what the computer is holding at each moment, something you can look at. That is where most bugs become obvious. The learning science behind it: Show a worked example first.
How to use it
Frequently asked questions
Is there an AI coding tutor that explains my code?
DuckyHelper runs your code against tests, shows expected against what it got, then plays it back step by step with every variable as it changes, so you see where it goes wrong. It explains out loud as it goes, and leaves the fix to you.
Which languages can it run?
It runs Python and JavaScript against tests, and the step-through player shows how Python runs. For code in other languages, DuckyHelper can still read it with you, explain it line by line and walk you through writing it.
Is there a code visualizer for learning?
Yes. Ask show me what this loop does and a step-through player opens: the line that runs next is highlighted, and variables, arrays and pointers are drawn as they change. Play, pause, or drag to any step.
Can it help me practice for coding interviews?
Yes. Talk through a problem out loud, run your solution against tests, and step through it when a case fails. On a Mac it works in any editor or coding site. Coding interviews with DuckyHelper has a plan.
Is my code safe?
Your code runs in a sandbox with no internet, so it cannot reach your files or the web. On a Mac, Ducky reads code from your screen only while the pill is open.
More features
Find the bug yourself
Press fn on your editor on a Mac, or open the Eddy tab, and ask why it gives the wrong answer.
