programming-for-dummies

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Creating Functions
If you don’t know how many times you need to repeat commands, use a
WHILE loop, which looks like this
while condition
Command
end
If the condition is True, the loop runs at least once. If this condition is
False, then the loop doesn’t run.
Ruby also offers a negated form of the WHILE loop called an UNTIL loop,
which looks like this:
until condition
Command
end
The UNTIL loop keeps running until a condition becomes True.
Somewhere inside a WHILE or an UNTIL loop, you must have a command
that can change the condition from True to False; otherwise the loop will
never end and your program will appear to hang or freeze.
Creating Functions
To break up programming problems, you can create subprograms that solve
a specific task. Such subprograms are functions or methods. The format of a
typical function looks like this:
def functionname (Parameter list)
Commands
return value
end
The two parts of a Ruby function are
✦ Parameter list: Defines any data that the function needs to work. If
the function doesn’t need to accept any values, omit the parentheses
altogether.
✦ Return: Defines a value to return.
If a function doesn’t return a value or accept any parameters, it might look
like this:
def myfunction
Command
end