The reason behind its popularity is the fact that it allows people to indicate in writing several functions:

Additionally it is also possible to write code that can learn for itself, writing new functions when it needs it.

Also note that Stroustrup is okay with writing short functions all on one line.

A useful way to write complex functions is the lambda calculus.

Seamans had written pattern-recognition functions for Amy's language use, enabling them to monitor her signing around the clock.

For these methods, we wrote functions to specify details such as the high and low frequency cutoffs with the filter, for example.

They cannot be used to write functions with posix behavior.

Nezval wrote this poem focusing on the forms, sounds, and functions of the alphabet.

Users can write functions for use in their code, and also procedures, which are functions with multiple outputs.

Mass storage devices store programs and data even when the power is off; they do require power to perform read and write functions during usage.