Methods and Functions

7. Methods and Functions

Methods, often referred to as functions in other programming languages, are blocks of code that perform specific tasks or computations. They are essential for organizing and reusing code in Java. In this Core Java tutorial, we'll delve into methods and functions, providing comprehensive explanations and examples.

Defining a Method:

In Java, a method consists of a method signature and a method body. The method signature defines the method's name, return type, and parameters (if any).

returnType methodName(parameter1Type parameter1Name, parameter2Type parameter2Name, ...) {
    // Method body
    // Code to perform the task
    return returnValue; // Optional, if the method has a return type
}

public int add(int num1, int num2) {
    int sum = num1 + num2;
    return sum;
}

In this example:

• The method's name is 'add' .
• It takes two parameters of type 'int' named  'num1' and 'num2'.
• It calculates the sum of 'num1' and 'num2'and stores it in a variable called 'sum'.
• Finally, it returns the value of 'sum'.

Calling a Method:

To use a method, you need to call it from another part of your program. To call a method, use its name followed by parentheses and pass any required arguments inside the parentheses.

int result = add(5, 3);
System.out.println("Sum: " + result); // Output: Sum: 8

In this example, we call the 'add' method with arguments '5' and '3', and it returns '8'. The result is stored in the 'result'variable, which is then printed to the console.

Method Overloading:

Method overloading allows you to define multiple methods with the same name but different parameter lists. Java determines which method to call based on the number and types of arguments passed.

public int add(int num1, int num2) {
    return num1 + num2;
}

public double add(double num1, double num2) {
    return num1 + num2;
}

In this example, we have two 'add' methods: one for  'int' arguments and another for  'double'arguments. Java will choose the appropriate method based on the argument types during the method call.

The 'void'Return Type:

If a method doesn't need to return a value, you can specify the 'void' return type. Such methods are used for performing actions without returning a result.

public void greet(String name) {
    System.out.println("Hello, " + name + "!");
}

String greeting = "Hello, World!";
int length = greeting.length(); // Returns the length of the string
System.out.println("Length of the string: " + length);