Method and Function
What is a method in object oriented programming? Explain the difference between a method and a function.
A method is the equivalent of a function in object-oriented programming. A noun is to a verb what a variable is to a method — the methods are the actions that perform operations on a variable. A method accepts parameters as arguments, manipulates these, and then produces an output when the method is called on an object. Methods are similar to functions, but methods are also classified according to their purpose in the class design. In classes, variables are called attributes, so methods often operate on attributes.
- Function — a set of instructions that perform a task.
- Method — a set of instructions that are associated with an object.
A function is a piece of code that is called by name. It can pass data to operate on (i.e. the parameters) and can optionally return data (the return value). All data that is passed to a function is explicitly passed.
A method is a piece of code that is called by a name that is associated with an object. In most respects it is identical to a function except for two key differences:
- A method is implicitly passed the object on which it was called.
- A method is able to operate on data that is contained within the class (remembering that an object is an instance of a class - the class is the definition, the object is an instance of that data).
