# Confused on excerise on htdp

**URL:** <https://racket.discourse.group/t/confused-on-excerise-on-htdp/768>\
**Category:** Questions & Answers\
**Tags:** question, drracket, creative-racket\
**Created:** [March 5, 2022, 12:15pm UTC](https://racket.discourse.group/t/confused-on-excerise-on-htdp/768 "2022-03-05T12:15:08Z")\
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**Author:** ![simonls](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/simonls/32/170_2.png) [@simonls](https://racket.discourse.group/u/simonls)\
**Post date:** [March 5, 2022, 2:20pm UTC](https://racket.discourse.group/t/confused-on-excerise-on-htdp/768/2 "2022-03-05T14:20:07Z")

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What does the exercise want you to do?

What is `boolean?` what does it expect as input, what is its output?  
What are functions ending with a question mark `?` called?  
Here is where functions are first introduced: [Prologue: How to Program](https://htdp.org/2018-01-06/Book/part_prologue.html#%28part._some-i%2Fo%29)

* * *

In general it seems you have skipped parts of the book and it is difficult to help you, because I don't know which parts you may have skipped. And me giving you the solution wouldn't help you in learning.

To make it easier to **help us, help you** , you should follow the **design-recipe** :  
[I Fixed-Size Data: 3.1 Designing Functions](https://htdp.org/2021-11-15/Book/part_one.html#(part._sec~3adesign-func))

This way it is **easier for other people** reading your code _to recognize what parts you already understand and which parts you need guidance with_.

**Following the design recipe is also for yourself** , because it structures a task in a way that **causes you to get clear** about what you are trying to accomplish and **it gives you a clear structure to follow** ,  
_this allows you to reach the goal incrementally, avoiding confusion_.

In general I advise you to go back to the beginning and see what parts you need to re-read, because there are definitely parts you have skipped, **those skipped parts now cause your confusion**.

* * *

Too be a bit more cheeky 😛: if you can't be bothered to follow the design recipe, then I can't be bothered to answer any more questions. (I am a volunteer and a lot of other people here are...)

Why? Because it is not productive if I replicate what **How to Design Programs** teaches, spread across a lot of different help topics.

If I can see that you can do what the book wants you to do:  
**follow the design recipe** and you still need help, then I am more inclined to spend my free time, volunteering to help someone.

There is a reason why netiquette is a thing, because with it, it is more likely that people want to answer.  
Within the context of **How to Design Programs** you should follow the design recipe.

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