Java Program to Check Number is Divisible by 3

In Java, to check if a number is divisible by 3, we can use either an if-else conditional statement or the ternary operator. This article focuses on learning through examples, detailed logic, and program explanations for better understanding.

Required Knowledge

• Java programming basics
• Java Operators
• Conditional Statements
• Ternary Operator

Problem Statement

We need to write a Java program to check if a number is divisible by 3. The program should take an integer as input and output whether the number is divisible by 3 or not. The above action should be done in our java program. Let’s look at an example what we have to achieve.

Example 1:

Input number: 5

Using the modulo operation: 5 % 3 = 2

Since the remainder is not 0, 5 is not divisible by 3.

Here for the input 5, Output is “It is not divisible by 3”, As 5 is not divisible by 3.

Example 2:

 Input number: 6

Using the modulo operation: 6 % 3 = 0

Since the remainder is 0, 6 is divisible by 3.

Here for the input 6, Output is “It is divisible by 3”, As 6 is divisible by 3.

Logic to check number is divisible by 3

There are multiple logics to check a given input is divisible by 3 or not in Java Programing language.

Logic 1: Using if-else

• Here, we are checking the remainder of the given input number.
• When a number is divided by 3, if the remainder is zero, the condition is satisfied, and the program prints “Number is divisible by 3.”
• If the remainder is not zero, the else block will execute and print “Number is not divisible by 3.”

if (number % 3 == 0)
	System.out.println("Number is divisible by 3");
else
	System.out.println("Number is not divisible by 3");

Logic 2: Ternary Operator

• This operator takes three operands and works similarly to if-else statements. If the condition is true, it prints the first expression; if the condition is false, it prints the second expression.
• When a number is divided by 3, if the remainder is zero, then the number is divisible by 3. Otherwise, it is not.

result=(number%3==0)? number+" is divisible by 3":number+" not divisible by 3";
		System.out.println(result);

Java Program to check number divisible by 3

Program 1: Using if-else

In the below program we are using if else to check number is divisible by 3 in Java.

import java.util.Scanner;

public class DivisbleByThree {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		System.out.println("enter the number");
		int number = s.nextInt();
		if (number % 3 == 0)
			System.out.println("Number is divisible by 3");
		else
			System.out.println("Number is not divisible by 3");
		s.close();
	}
}

Output:

enter the number
15
Number is divisible by 3

Program Explanation to check num divisible by 3

• The program imports the Scanner class to enable user input.
• It defines a class named DivisibleByThree.
• In the main method:
• Creates a Scanner object s to read user input.
• Asks the user to enter a number.
• Reads the integer input and stores it in number.
• Checks if the number is divisible by 3 (i.e., has no remainder when divided by 3).
• If the condition is true, it prints “Number is divisible by 3”.
• If the condition is false, it prints “Number is not divisible by 3”.
• Closes the Scanner object to release system resources.

Program 2: Using Ternary Operator

In the below program we are using Ternary Operator to check number is divisible by 3 in Java.

import java.util.Scanner;

public class DivisbleByThree {

	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		System.out.println("enter the number");
		int number = s.nextInt();
		String result;
		result=(number%3==0)? number+" is divisible by 3":number+" not divisible by 3";
		System.out.println(result);
		s.close();
	}
}

Output:

enter the number
3217
3217 not divisible by 3

Program Explanation to check num divisible by 3

• The program imports the Scanner class to allow user input.
• It defines a class named DivisibleByThree.
• In the main method:
• Creates a Scanner object s to read user input.
• Asks the user to enter a number.
• Reads the integer input and stores it in the variable number.
• Uses a ternary operator to assign the appropriate message to the variable result based on whether the number is divisible by 3 or not.
• Prints the result message.
• Closes the Scanner object to release system resources.

Conclusion

In this article, we explored how to check if a number is divisible by 3 using conditional statements like if-else and the ternary operator. We understood the logic behind this and moved on to writing the program.

For more information on related topics, you might find these articles helpful:

• Understanding the concepts of Conditional statements in Java.
• Concepts of operators in Java
• Top 10 Programming tips in Java

We hope you find this article helpful. If you have any questions or need clarification, please leave a comment below. Don’t forget to subscribe to our newsletter for more updates on Java programming tips and tutorials.

Happy Learning!!