Methods

What is a method? - In Java, a **method** is a block of code that performs a specific task. Think of it this way, a **method** is a set of coding instructions which can be referenced by name, and called at any point in a program by simply using the method's name. The main purpose of writing methods is code reusability, which implies that the code is written once, and then can be used over and over. Additionally, methods are useful when breaking down complex programs into smaller, more manageable pieces. A method would then be written to solve the smaller piece, and would be called from the main program or another method. Methods can be called from other parts of the program, making it easy to reuse code and make changes to the program's behavior. The Parts of a Method - - **method declaration**: The only required parts of a method declaration are the method's ***return type***, ***name***, a ***pair of parentheses*** `()`, and a ***body between braces*** `{}`. - **method signature**: Two of the components of a method declaration comprise a **method signature** — the method's ***name*** and the **parameter types**. (***Note**: a method signature does not contain anything else.*) - There are other parts that can be used when writing a Java method. The complete list of **components of a method declaration** are as follow: -**Modifiers**: Access Modifiers (e.g. `public`, `private`, `protected`) or Non-Access Modifiers (e.g. `static`) -**Return Type**: Either the data type (primitive or reference) of the value to be returned by the method, or `void` (no return value) -**Method Name**: A name give to the method, following the rules for field names, written in camelCase format. -**Parameter List**: Either `()`, or a list of input parameters, comma-delimited, preceded by the data type, enclosed in `()`. -**Exception List**: This is a list of **Exceptions** that can be thrown by the method -- Error Handling. -**Method Body**: the code written, enclosed in `{}`
Method Declaration - When writing a method, you need to specify its **name**, **return type**, and any **parameters** it may take, as well as write a **body** which contains the functionality of the method. - The **name** of the method should be descriptive and indicate what the method does. - The **return type** specifies the type of data that the method will return, and if the method does not return any data, its return type is `void`. - Any **parameters** are optional and allow you to pass data to the method when it is called if required. - The **body** will contain any Java statements that accomplish the purpose of the method. Example Method Declaration - public int calculateSum(int number1, int number2) { return number1 + number2; }
Method Invocation - To call a method, you simply use its **name** followed by **parentheses** `()`, and any necessary **arguments** within the parentheses. The method will then execute its code, and may `return` a value if a return type other than `void` is specified. Example Method Invocation - int num1 = 5; int num2 = 5; int sum = calculateSum(num1, num2);
Conclusion - Using **methods** in Java can help make your code more modular, efficient, and easier to understand. It also allows you to reuse code and avoid repeating the same code over and over again. By learning how to use methods effectively, you can become a more proficient and efficient Java programmer.

Java Week 3 - Methods