Since we're at an electronics forum, here are programs I devised which are electronics related. All were written in BASIC language.
* (a) input an inductor value, (b) calculate what capacitor value will combine to yield a desired resonant frequency.
* (a) read data statements containing price and dimensions of perfboards available at Radio Shack, (b) calculate cost per square inch.
* (a) input a tv broadcast frequency, (b) calculate length of several wire elements for a yagi antenna.
* (a) read data statements containing volt and ampere readings from photovoltaic panels, (b) create a graph overlaying volts, amps, watts.
* same as above for my homemade power supply.
* Detect when an appliance turns on and off, keep record of times and duration.
* Input morse code beeps real-time, translate into English characters onscreen.
* print a graph displaying Ampere draw from my 24V battery bank, to obtain a desired load at 120 VAC.
* Homemade program to simulate analog circuits. Animated, interactive. Save and load circuits. Option to create movie file of simulation.