Tikal-25

The original calculator this app is based on just developed a malfunction after nearly 50 years in use, so I decided to transfer it to the iPhone. It provides arithmetic, trigonometric, logarithmic and statistical functions and fairly high internal precision with an 8 digit standard display mode, and a scientific notation mode with 5 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 emulates. 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 it blue instead of red though there were no blue LEDs in 1978. Appears to be much freindlier to the eye though. A later version will probably have a configuration option for the colors.

The app runs in portrait mode on iPhones for the authentic pocket calculator feeling. Future versions may provide a greater variety in skins and functionality if I ever come around to that, and there is sufficient demand...

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

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...