Nested If Example in Java

Introduction

Nested If is a classic Java console program that demonstrates the concept with complete source code and sample output. Conditional statements choose different code paths based on boolean expressions.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Definition

A nested if statement is an if-else statement with another if statement as the if body or the else body. Here’s an example: if ( num > 0 ) // Outer if if ( num < 10 ) // Inner if System.out.println( “num is between 0 and 10” ) ; There is an outer if statement, and an inner if.

Syntax

if (condition){
	if (condition){
		//Do something
	}
	//Do something
}

Nested If Example Program

import java.util.Scanner;
public class NestedIfDemo {
	public static void main(String args[]){
		Scanner in=new Scanner(System.in);
		System.out.print("value of x: ");
		int x =in.nextInt();
		System.out.print("value of y: ");
		int y =in.nextInt();
		if( x == 100 ){
			if( y == 10 ){
				System.out.print("X = 100 and Y = 10");
			}
		}
		else{
			System.out.println("The values of x and y are not 100 and 10 simultaneously");
		}
	}
}

Sample Output

value of x: 56
value of y: 34
The values of x and y are not 100 and 10 simultaneously

When to use

Use this nested if example when learning or revising core Java syntax.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. import java.util.Scanner; imports a class used later in the program.

3. A Scanner reads typed input from the keyboard (System.in).

4. A println / print call writes text to the console — part of the sample output below.

5. int x =in.nextInt(); updates a variable used in the calculation or output.

6. A println / print call writes text to the console — part of the sample output below.

7. int y =in.nextInt(); updates a variable used in the calculation or output.

8. The if statement runs the nested code only when the condition is true.

Best Practices

• Use meaningful variable and class names that describe their purpose.
• Compile and run the program locally — modify values to see how output changes.
• Read compiler errors carefully; they usually point to the exact line to fix.

Common Mistakes

• Copying code without understanding each line — practice by changing one statement at a time.
• Mismatching the public class name and the .java filename.
• Forgetting semicolons at the end of statements.