Functions and return

A function is a small machine with a name: you put something in, it does some work, and it hands something back. What you put in is the input (a parameter); what it hands back is the return value.

1def solve(key):
2    answer = key + 1
3    return answer

def defines the function, solve is its name, key is its input. The indented lines are its inside. return hands the answer out and ends the function.

Every task on this site asks you to write a solve function. The task calls it with different inputs and looks at what you return. You do not pick the input; you write the rule that gives the right answer whatever comes in.

Tasks