[londons_explore]

Not me but a friend. Things like making electronics for singing birthday cards and toys that make noise.

But there are plenty of other similar things - like making the code that determines the flashing pattern of a bicycle light or flashlight. Or the code that does the countdown timer on a microwave. Or the code that makes the 'ding' sound on a non-smart doorbell. Or the code that makes a hotel safe open when the right combination is entered. Or the code that measures the battery voltage on a USB battery bank and puts 1-4 indicator LED's on so you know how full it is.

You don't tend to hear about it because the design of most of this stuff doesn't happen in the USA anymore - the software devs are now in China for all except high-end stuff.

[furyofantares]

Do any of those need a string formatting library?

[toast0]

Hotel safe might, if it logs somewhere (serial port?).

The others may have a serial port setup during development, too. If you have a truly small formatter, you can just disable it for final builds (or leave it on, asssuming output is non blocking, if someone finds the serial pins, great for them), rather than having larger rom for development and smaller for production.

[londons_explore]

mostly used for debugging with "printf debugging" - either on the developers desk, or in the field ("we've got a dead one. Can you hook up this pin to a USB-serial converter and tell me what it's saying?")