# Data Structure Display vs Recallio

The clearest difference is device support: Data Structure Display at 4 against Recallio's 2. Data Structure Display also leads on iOS requirement (13.0 vs 26.2). On price, ads and in-app purchases there is nothing between them.

Both are free to download. Data Structure Display sells 1 one-off in-app purchase and Recallio sells 2 in-app purchases, starting at $3.99 per month. Whichever you choose, the download price is not the number that matters.

## The numbers

| Metric | Data Structure Display | Recallio |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (676 ratings)](https://appshunter.io/ios/app/data-structure-display/id1455489695/reviews)** | — |
| Number of ratings | **676** | — |
| Positive reviews | 61.9% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 5 months | — |
| Monetization | Free with in-app purchases | — |
| Size | 8 MB | 3 MB |
| Requires iOS | **13.0** | 26.2 |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Jinan Matrix Information Technology Co., Ltd.](https://appshunter.io/developer/1009091575) | [Makarand Koli](https://appshunter.io/developer/1867788459) |

## What reviewers say

### Data Structure Display

[App page](https://appshunter.io/ios/app/data-structure-display/id1455489695)

Explore and learn data structures through dynamic debugging and visual observation of changes. This app covers linear structures, trees, graphs, and recursive algorithms like the Tower of Hanoi, offering interactive learning experiences.

**Highlights:** Dynamic data structure debugging, Visual observation of data structure changes, Learn linear structures (arrays, lists, queues, stacks), Explore tree structures (binary, AVL, red-black, heap), Understand graph structures and algorithms, Debug recursive algorithms like Tower of Hanoi

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock all data structures | $2.99 | one-time |

**What reviewers like**

- 📚 Excellent for DSA learning and studying
- ✨ Interactive components and pseudo code quality
- 👍 Good reference material for beginners
- 🎓 Unique educational content

**What reviewers complain about**

- 🔒 90% of content locked behind $2.99 paywall
- 📖 Incomplete coverage of data structures
- ✍️ Poor grammar and spelling
- 📱 No dark mode support on macOS
- 🔔 Excessive review prompts

**Reported bugs**

- Aggressive review request frequency
- Inconsistent dark mode functionality between iOS and macOS

**Requested features**

- Dark mode implementation
- Comprehensive coverage of all data structure variants
- More practical exercises and problems
- Ad-supported free tier instead of paywall


### Recallio

[App page](https://appshunter.io/ios/app/recallio-smart-flashcards/id6757604336)

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Recallio Pro | $3.99 | per month |
| Recallio Pro | $29.99 | per year |


## Frequently asked questions

### Is Data Structure Display free?

Data Structure Display is free to download, with in-app purchases available.

### Is Recallio free?

Recallio is free to download, with in-app purchases available.

### Do Data Structure Display or Recallio have ads?

Neither Data Structure Display nor Recallio shows ads.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*