Methods

A method is a block of code which only runs when it is called. You can pass data, known as parameters, into a method. Methods are used to perform certain actions, and they are also known as functions.

Why use methods? To reuse code: define the code once, and use it many times.

Method Declaration

public static int myMethod(int x) {
  return 5 + x;
}

• public: Access modifier.
• static: Method belongs to the Main class and not an object of the Main class.
• int: Return type. void if it returns nothing.
• myMethod: Name of the method.
• int x: Parameter.

Calling a Method

public static void main(String[] args) {
  myMethod(3); // Prints nothing, but returns 8
  int result = myMethod(10);
  System.out.println(result); // Prints 15
}

Method Overloading

With method overloading, multiple methods can have the same name with different parameters.

int myMethod(int x)
float myMethod(float x)
double myMethod(double x, double y)

[!NOTE] Multiple methods can have the same name as long as the number and/or type of parameters are different.

Scope

Variables declared inside a method are available only inside that method. This is called block scope.

Interactive Code

Create your own calculator using methods!

Quiz

Next Steps

Methods use variables. But where do these variables live in the computer? Let's check out Memory Management.