Java Tutorial - If..Else If..Else

This is a Java program that demonstrates how to use an if statement to conditionally execute code based on the value of a variable. 

public class Main {

	public static void main(String[] args) {
		int testNumber = 10; 
		
		if (testNumber < 20) {
			System.out.println("testNumber is smaller than 20");
		} else if (testNumber > 20) {
			System.out.println("testNumber is greater than 20");
		} else {
			System.out.println("Equal Numbers");
		}			
	}	
}

Explanations: 

int testNumber = 10;

This line declares a variable named testNumber of type int, and assigns it the value 10. 

if (testNumber < 20) {
    System.out.println("testNumber is smaller than 20");
} else if (testNumber > 20) {
    System.out.println("testNumber is greater than 20");
} else {
    System.out.println("Equal Numbers");
}

This block of code uses an if statement to conditionally execute code based on the value of testNumber.

The if statement checks whether testNumber is less than 20, and if it is, it executes the code inside the curly braces.

If testNumber is not less than 20, it moves on to the next condition, which checks whether testNumber is greater than 20. If it is, it executes the code inside the curly braces.

If testNumber is not less than 20 and not greater than 20, it executes the code inside the else block.

In this example, since testNumber is less than 20, the program executes the code inside the first curly braces, which prints the message "testNumber is smaller than 20" to the console.

That's it! This program demonstrates how to use an if statement to conditionally execute code based on the value of a variable.

The if else if else statement is important in programming because it allows you to perform conditional branching, where the program can execute different blocks of code depending on the values of one or more conditions.

In programming, parentheses () are used with the if else statement to enclose the condition that is being evaluated. The condition is typically an expression that evaluates to either true or false.

We use parentheses with the if else statement for two main reasons:

1. To define the condition: The parentheses help to define the condition that is being evaluated. Without them, the if else statement would not know what to evaluate as the condition.

2. To group the condition: Parentheses can be used to group multiple conditions or to specify the order in which the conditions should be evaluated. This is important because it ensures that the conditions are evaluated in the correct order and that the logic of the program is correct.

else is a keyword in programming that is used in conjunction with the if statement.

It is not mandatory to include an else statement with an if statement. You can use just an if statement if you only want to execute a block of code when the condition is true, and you do not need to provide any alternative code for when the condition is false. However, if you want to specify a block of code that is executed when the condition is false, then you must include an else statement.