# 20 Questions

> Classic guessing game teaching binary tree data structures. (iPhone/iPad app by Steven Curtis.)

- Source: https://appshunter.io/ios/app/20-questions/id1241872884 (this page in markdown: same URL + `.md`)
- Developer: [Steven Curtis](https://appshunter.io/developer/513736269)
- Category: Education
- Price: Free
- Rating: 1.77/5 from 31 App Store ratings · 44 written reviews indexed
- Age rating: 4+
- Requires: iOS 10.2 · 14 MB
- Languages: English
- Released: 2017-05-30
- Data updated: 2026-06-10
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/20-questions/id1241872884/reviews.md

## What is 20 Questions?

The classic parlour game with a twist, you can see how the computer is storing answers as you go along.

The idea is that you "teach" your iPhone how to play the game, and see how the data is stored in a binary tree.

Your iPhone (or iPad) learns from your answers and stored them on your phone, becoming more and more intelligent over time. 

A wonderful education tool for learning about binary trees (look at the worksheet pack on www.studeapps.binarytrees) for full information about how this App helps you to learn about this important computer science concept.

## Key features

- Classic guessing game gameplay
- Observe real-time data storage
- Learn binary tree concepts
- Device learns and becomes more intelligent
- Educational tool for computer science

## Recent user reviews (10 of 44)

All indexed reviews: https://appshunter.io/ios/app/20-questions/id1241872884/reviews.md

### 2/5 — It’s horrible

*2024-03-31*

I hate this game because I don’t get it I serched 20 questions and I tried this the first thought about this was I HATE this so I don’t like it.

### 5/5 — Love this game!!!

*2023-10-25*

I had this game when I was a kid. It was called the Animals Game and worked just like this. Maybe on Apple 2 plus on a floppy disk. It was so much fun and super funny when we made errors. I wanted to recreate it but here it is so thank you!!!
Requests:  1.  I can’t see the new word being entered. It’s white on white. 
2. It would be really fun to be able to play with someone remotely on the same game. Can you enable that?  
Thank you for making this game available!!! ❤️

### 3/5 — It’s ok

*2022-05-23, version 1.01*

I personally think this is fun. I like it as an easier way to create a binary tree, but there’s no way to correct a mistake. I accidentally put that a lion is a common household pet instead of changing the answer to no before submitting it. I went to go change the answer or delete that one answer in my tree, only to discover I couldn’t. So I deleted the entire tree, and am now deleting the app. I also don’t want the answers that every tree starts with automatically, but again, no way to delete them. Just give me a blank tree or a way to edit it.

### 1/5 — WHAT!?

*2021-08-02, version 1.01*

What in the seven hells is this. Fish or table??? That’s it!?

### 2/5 — Not quite

*2021-03-07, version 1.01*

I really wanted this to work - I wrote a similar thing for a ZX Spectrum back in the day and I wanted to see the same thing in action after all these years but the app is fundamentally flawed. The fish node can never be extended because the app assumes it has won if you answer, “Yes” to “Is it a fish?”. No opportunity to add what kind of fish it was. If you could remove the fish question and start from scratch then it’d be fine but deleting the tree doesn’t remove the example questions. Plus, the font is invisible when you type in the animal you were thinking of. The idea is great - just needs fixing!

### 5/5 — Does what it says! Might need title as education tool

*2020-12-31*

Probably isn’t clear to people from the title it’s not a game.

### 1/5 — TERRIBLE

*2020-03-27, version 1.01*

It only knows Whale and Table, so if you’re not thinking of one of those, too bad.

### 1/5 — Wow

*2019-07-16*

Usually don’t write reviews but wow. Basically teaching the COM how to play when really, I’m just tryna play

### 1/5 — Garbage

*2019-07-15, version 1.01*

Quite literally the worst game ever. Stop wasting my time with this.

### 1/5 — It wasn’t a whale!

*2019-05-25, version 1.0*

The games great if you have the comprehension of a potato!

## Frequently asked questions about 20 Questions

### What is this app about?

This app is a digital version of the classic '20 Questions' guessing game. It uniquely allows users to see how the game's answers are stored internally using a binary tree data structure. The app is designed to be an educational tool for learning about this fundamental computer science concept.

### How does the app teach about binary trees?

As you play the game, the app stores your answers and the computer's learned responses within a binary tree. You can observe this process, providing a visual and interactive way to understand how data is organized and accessed in this structure. Additional learning resources are available on the developer's website.

### Is this app free to use?

Yes, the application is available for free. There are no advertisements or in-app purchases mentioned, indicating a completely free experience for users.

### What devices is this app compatible with?

The app is designed to run on iPhones and iPads. Specific iOS version compatibility is not detailed, but it is intended for Apple mobile devices.

### Who would benefit from using this app?

This app is ideal for students, educators, or anyone curious about computer science fundamentals, particularly data structures like binary trees. It offers a fun and engaging way to grasp these concepts beyond traditional textbook learning.

## Version history (last 2 releases)

### 1.01 — 2019-05-30

Added tutorial, and changed colour scheme to dark mode.

### 1.0 — 2017-05-30

No release notes.

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## More apps by Steven Curtis

- [Computer Science GCSE Revision](https://appshunter.io/ios/app/computer-science-gcse-revision/id524383316)
- [PE GCSE](https://appshunter.io/ios/app/pe-gcse/id646554938)
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- [Teacher Timer](https://appshunter.io/ios/app/teacher-timer/id782391884)
- [Classroom Noise Monitor](https://appshunter.io/ios/app/classroom-noise-monitor/id811273381)
- [VAT Calc HD](https://appshunter.io/ios/app/vat-calc-hd/id932108233)

All apps by Steven Curtis: https://appshunter.io/developer/513736269

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*