Graycode vs 开心听书
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Graycode
This utility converts numbers between decimal, hexadecimal, binary, and Gray code formats. Changes to one value automatically update the others, making it a convenient tool for engineers. It also features an animated demonstration of the Tower of Hanoi puzzle.
- Decimal, hex, binary, Gray code conversion
- Real-time updates
- Handy calculator for engineers
- Animated Tower of Hanoi solution
- Supports iPhone, iPad, iPod
Read full descriptionHide full description
This app is used to convert numbers among decimal, hex, binary and gray code. If a user changes any one of these numbers, the other ones will change accordingly. It is a handy calculator for engineers to obtain the binary or gray code values from a decimal, or vise versa. In addition, an animated solution of a Hanoi Tower with three disks is also demonstrated based on the input number.
开心听书
Listen to a wide variety of books daily, including classics, educational content, and popular series. Offers daily updates and various subscription options for unlimited access.
- Daily audiobook listening
- Extensive book library
- Daily updates
- Subscription plans
- Parental education content
Read full descriptionHide full description
每天听书，有声读书 包含百家讲坛，365读书，读书有范，枕边读书会，有书·陪你读书，十点读书，《论语》朗读与讲解，读书有范 | 亲子教育，陪你读书|十分钟带你读完一本名著，红楼梦-原著原文朗读与讲解等 每天更新 【超级会员连续包月套餐说明】 订阅周期：一个月（连续包月产品） 订阅价格：连续包月产品为每月3元 付款：苹果iTunes账户会在订阅到期前24小时内扣费，扣费成功后订阅顺延一个周期 取消订阅：如需取消订阅，请在当前订阅周期到期前24小时以前，手动在iTunes/Apple ID设置管理中关闭自动续订功能 【超级会员连续包年套餐说明】 订阅周期：一年（连续包年产品） 订阅价格：连续包月产品为每年12元 付款：苹果iTunes账户会在订阅到期前24小时内扣费，扣费成功后订阅顺延一个周期 取消订阅：如需取消订阅，请在当前订阅周期到期前24小时以前，手动在iTunes/Apple ID设置管理中关闭自动续订功能 【超级会员永久套餐说明】 有效周期：永久（一次性付费产品） 价格：永久会员价格为30元 隐私政策：https://shimo.im/docs/CPcjDWw9rK6pKTd8/ 用户协议：https://shimo.im/docs/VwXhvdYx8xtxYqqH/ 技术支持： https://shimo.im/docs/pJQDpWwj6DXq6TdJ/
Screenshots
Verdict
The clearest difference is review sentiment: Graycode at 67% against 开心听书's 0%. Graycode also leads on in-app purchases (none vs 4). 开心听书's advantage is price (Free vs $2.99) and update cadence (every 2 weeks vs every 10 months). On ads, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
开心听书 is free to download; Graycode costs $2.99 up front. 开心听书 sells 4 in-app purchases, starting at $0.49 per month. Graycode asks for nothing beyond the download.
Graycode ships an update every 10 months, 开心听书 every 2 weeks. The most recent releases landed on September 25, 2026 and September 30, 2026 respectively.
| Parameter | Graycode | 开心听书 |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 3.0 (2 ratings) — better | — |
| Positive reviews | 66.7% of reviews — better | 0.0% of reviews |
| Number of ratings | 2 — better | — |
| Update frequency | Every 10 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Freemium — better |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 12.0 — better | 13.0 |
| Further details — not scored | ||
| Size | 2 MB | 12 MB |
| Age rating | 4+ | 4+ |
| Developer | Duo Pisceses, Inc. | 滨亮 马 |
Customer experience
Graycode
开心听书
In-app purchases
Graycode
No in-app purchases
开心听书
- 超级会员连续包月$0.491 Month
- 超级会员连续包年3 Days trial$1.991 Year
- 超级会员连续包周3 Days trial$5.497 Days
- 超级永久会员$4.99
