Opposed to this is a 'runtime' of a program - it happens when (and after) program is executed. The remaining data is given to program perhaps, and it decides of it's behaviour in details, determines it, more or less. Program's behaviour also depends on computer hardware, other programs, operating system, even laws of physics, weather, and so on...
Computer Laboratory: a little 'C' exercise.
C is very well known and popular professional programming language.
Such experiments as above, tell programmer about properties of a programming language and computer system's qualities. They are not formal proofs, just experiments that give approximate results, but not always work the same way.