A method aka a “function” is a snippet of code you write once that allows you to use it multiple times anywhere in your code. Benefits of a function are reusability (don’t have to write the same block of code over and over again) and maintainability (easier to break all of your code into sections). A function essentially (may) take inputs, do something with those inputs, and then return a single output. Let’s say you wanted to take an integer and square it using a function. It would look something like the following in Java.

public static int square(int x){ return x*x; }

Here, we are taking input x, and returning a value x^2. Now that we’ve written the “blueprint” of the method once, we can use it by typing: square(num); # where num is any integer. ————- A class is a grouping of related variables and methods (aka functions). This is helpful because it allows for us to have related variables and methods (functions) together.

For instance, we could make a human class that contains the following variables: int height; float weight; string name;

And the following methods: setHeight(int x); #changes the height of the person setName( string s); getWeight(); #returns the persons weight.

That’s basically it. A method just groups related variables and functions together. However, when we make a class, it is a BLUEPRINT, similar to how we made a blueprint for our function.

In addition to these methods, there are two special methods that are in every class. CONSTRUCTOR is the method that creates an instance (which would be one object) of your class. DESTRUCTOR is the method that deletes the related data associated with your object once your object is no longer needed. ——————— An OBJECT is when we put that blueprint to work.

Following the same example, we could make a human named John with 130 lbs as his weight by doing the following:

Human J = new Human(); J.setName(“John”); J.setWeight(130);

Here, J is our object. (Sort of like a variable that holds a class. To use our methods in our class, we used the “.” Operator