This calculator app is loosely based on a pocket calculator designed in Japan in 1978. It provides arithmetic, trigonometric, logarithmic and statistical functions and fairly high internal precision with a display mode of 8 digits in portrait and 12 digits in landscape mode, which can be interchanged freely while entering numbers, and a scientific notation mode with 5/9 digits mantissa and 2 digits exponent. Internally it uses Decimals for primitive operations and Double floating point numbers for everything else, so in general it should be somehow more accurate than the original calculator model it was based on. I added a graph display for the statistical mode, a shareable calculation log, a manual (all accessible by tapping on the title line above the buttons) and a random number function that produces random numbers in the range [0..1].

The operational correctness is checked with unit tests. All examples from the original manual work with the same or with higher accuracy. There are about 45 unit tests until now covering different combinations, which should be sufficient for everyday educational or household calculations. The unit test set will be further expanded with future versions.

The app does not store or transmit any data apart from the user-initiated log file sharing, it just needs permission to install and use the included 7 segment font for emulating the LCD display. There are no advertisements. The "OFF" Button exits the application immediately. Localizations for other languages are in preparation, this mainly concerns the manual and translations in the additional views. The main display uses a universal standard 7-segment display without localization options for clarity. The dark mode aims at a LED effect instead of LCD. Made the default blue instead of red, though there were no blue LEDs in 1978. In the settings you can choose from red, green or blue for now.

The localizations may still contain errors and missing translations.

Segment7Standard font license: SIL Open Font License (OFL)
Link: https://www.fontspace.com/segment7-font-f19825

Music in App Previews: Excerpts from Gustav Holst, "The Planets": "Mercury the Messenger" and "Neptune the Mystic", performed by the London Symphony Orchestra, conducted by Gustav Holst, published by Columbia 1923, Recording in the Public Domain
Link: https://imslp.org/wiki/The_Planets,_Op.32_(Holst,_Gustav)

Known issues:
- Klingon mode shows an obfuscated log that still does not make much sense.This is because Klingon ist not integrated into Unicode, and logging is probably not compatible with the Klingon honor code anyway.

Written in Swift 5. This application is completely free of AI, so you can be fairly sure only human errors are to be reckoned with...