Functions in Java

Lecture 41:- Functions in Java

In Java, functions are called methods. A method is a block of code within a class that performs a specific task or operation. Methods are used to organize code, make it reusable, and improve code readability. In Java, methods can be defined within a class, and they can have a return type (e.g., int, double, void, etc.) and parameters (input values). Here's the syntax to define a method in Java:

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accessModifier returnType methodName(parameterType parameter1, parameterType parameter2, ...) {
    // Method body (code)
    // It may or may not have a return statement based on the returnType.
}

• accessModifier: Specifies the visibility of the method (e.g., public, private, protected, or package-private/default).
• returnType: Specifies the data type of the value that the method returns. Use void if the method does not return anything.
• methodName: The name of the method.
• parameterType: The data type of each parameter (if any) that the method takes.
• parameter1, parameter2, ...: The names of the parameters passed to the method. These are used as variables within the method's body.

Let's see an example of a simple method in Java:

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public class MathOperations {
    // A method to add two integers and return the result
    public int add(int num1, int num2) {
        int sum = num1 + num2;
        return sum;
    }

    // A method with no return value (void)
    public void printMessage() {
        System.out.println("Hello, World!");
    }

    public static void main(String[] args) {
        MathOperations math = new MathOperations();
        int result = math.add(5, 7);
        System.out.println("Result of addition: " + result);

        math.printMessage();
    }
}

Output:

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Result of addition: 12
Hello, World!

In the example above, we define a class MathOperations with two methods: add and printMessage. The add method takes two integers as parameters, adds them, and returns the result. The printMessage method has no return type (void) and simply prints a message to the console.

In the main method, we create an instance of the MathOperations class, call the add method with arguments 5 and 7, and store the result in the result variable. We then print the result using System.out.println. Next, we call the printMessage method to display the message "Hello, World!" on the console.

Methods play a crucial role in Java programs as they encapsulate functionality, promote code reusability, and make programs easier to maintain.

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