# NBack for iPad vs Data Structure Display

The clearest difference is price: Data Structure Display at Free against NBack for iPad's $2.99. Data Structure Display also leads on ratings volume (676 vs 1) and update cadence (every 5 months vs every 12 months). NBack for iPad's advantage is rating (5.0 vs 4.5) and in-app purchases (none vs 1). On ads there is nothing between them.

Data Structure Display is free to download; NBack for iPad costs $2.99 up front. Data Structure Display sells 1 one-off in-app purchase. NBack for iPad asks for nothing beyond the download.

NBack for iPad holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: Data Structure Display has 676 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 50% of NBack for iPad's written reviews are positive against 62% of Data Structure Display's, so the app with the better star average is not the one people write more warmly about.

NBack for iPad ships an update every 12 months, Data Structure Display every 5 months. The most recent releases landed on September 16, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | NBack for iPad | Data Structure Display |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/nback-for-ipad/id504739398/reviews)** | [4.5 (676 ratings)](https://appshunter.io/ios/app/data-structure-display/id1455489695/reviews) |
| Number of ratings | 1 | **676** |
| Positive reviews | 50.0% of reviews | **61.9% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 12 months | **Every 5 months** |
| Monetization | Paid | **Free with in-app purchases** |
| Size | 3 MB | 8 MB |
| Requires iOS | 18.2 | **13.0** |
| Devices | iPad | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Yasuyoshi Ota](https://appshunter.io/developer/1500357652) | [Jinan Matrix Information Technology Co., Ltd.](https://appshunter.io/developer/1009091575) |

## What reviewers say

### NBack for iPad

[App page](https://appshunter.io/ios/app/nback-for-ipad/id504739398)

This application offers a cognitive training tool designed to enhance working memory and mental acuity. It utilizes the N-Back task, a scientifically recognized method for improving cognitive abilities. Users can train their memory through various levels of difficulty.

**Highlights:** Working memory training, N-Back task implementation, Multiple difficulty levels (1'Back to 10'Back), Cognitive ability enhancement, iPad optimized

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### 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


## Frequently asked questions

### Is NBack for iPad free?

NBack for iPad costs $2.99, with no in-app purchases.

### Is Data Structure Display free?

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

### Which has better reviews, NBack for iPad or Data Structure Display?

NBack for iPad is rated higher. NBack for iPad averages 5.0 out of 5 from 1 ratings, while Data Structure Display averages 4.5 from 676 ratings.

### Do NBack for iPad or Data Structure Display have ads?

Neither NBack for iPad nor Data Structure Display shows ads.

### Which is updated more often, NBack for iPad or Data Structure Display?

NBack for iPad ships an update every 12 months, and Data Structure Display every 5 months. Most recently, NBack for iPad was updated on September 16, 2026 and Data Structure Display on September 24, 2026.

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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.*