What makes a method

What makes a method

There are four things that constitute a method:

• a name
• a block of code
• (optionally) accepting input
• returning output

Not all methods actually need input (so they don’t take any), and not always do we care about the output that a method returns.

Imagine a vending machine where you can chip in some money, press some buttons, and the machine will spin a few gears and wheels, and spit out the chocolate bar you were after.

If the vending machine was a method, then your money, as well as the buttons you press are the input. The way the machine internally spins certain mechanics is the block of code , the stuff it does internally. And the product that it dispenses is the return value.

Although this would be an odd thing to mention to a non-programmer, we could say that a vending machine is a way of “transforming” money and data into chocolate.

Methods are a lot like that.

Methods have a name, take some input, do something with it, and return a result.

Programmers usually don’t use the term “input” in this context. Instead we say that a method accepts a number of arguments (pieces of input). And instead of “output” we use the term return value : the thing that we get back from the method.

A method’s input is referred to as “arguments”, while its output is called a “return value”.

This will become more clear in the following chapters. Let’s define a method next.