The reverse of a given number is simply called as when the number is 123, the reverse number should be 321. In java, there are multiple ways to calculate the reverse of a given number. Here we will discuss a simple way using a while loop.
Follow the below steps to calculate the reverse of a number,
- First find the last digit of given number (calculating the remainder by dividing the number by 10).
- Now multiply the variable reverse by 10 and add the calculated remainder of previous step.
- Remove the last digit from the number by dividing the number by 10.
- Repeat the above 3 steps inside while loop until the number become 0.
Let’s see the complete logic to calculate the reverse of a given number,
Solution
ReverseNumber.java
package com.javacodepoint.programs;
import java.util.Scanner;
public class ReverseNumber {
public static void main(String[] args) {
// Taking input from the user to reverse
System.out.print("Enter an integer number:");
// Reading user input using Scanner object
int number = new Scanner(System.in).nextInt();
//Initiating reverse variable with 0
int reverse = 0;
int tempNumber = number;
// while loop will continue until the number become 0
while(number > 0) {
//Finding the last digit of the number
int remainder = number % 10;
//Calculating the reverse by multiplying it with 10 and adding remainder (last digit)
reverse = reverse * 10 + remainder;
//Removing the last digit from the number
number = number / 10;
}
System.out.print("The reverse of the given number is = "+reverse);
}
}
OUTPUT:
Enter an integer number: 12345
The reverse of the given number is = 54321