In this post you will learn basic java program that reverses the digits of a number and print the reversed number.
Problem:
Here is the example of the problem –
Example 1:
Input : 5678 Output :8765
Example 2:
Solutions:
- First, we find the remainder of the given number by using the modulo (%) operator.
- Multiply the variable reverse by 10 and add the remainder into it.
- Divide the number by 10.
There are three ways to reverse a number in java:
- Reverse a number using while loop.
- Reverse a number using for loop.
- Reverse a number using recursion.
Approach 1 : Reverse a number using loops
public class ReverseNumber
{
public static void main(String[] args)
{
int number = 12345, reverse = 0;
while(number != 0)
{
int remainder = number % 10;
reverse = reverse * 10 + remainder;
number = number/10;
}
System.out.println("The reverse of the given number is: " + reverse);
}
}
Output:
The reverse of the given number is: 54321
Approach 2 : Reverse a number using recursion:
import java.util.Scanner;
public class ReverseNumber
{
//method for reverse a number
public static void reverseNumber(int number)
{
if (number < 10)
{
//prints the same number if the number is less than 10
System.out.println(number);
return;
}
else
{
System.out.print(number % 10);
reverseNumber(number/10);
}
}
public static void main(String args[])
{
System.out.print("Enter the number that you want to reverse: ");
Scanner sc = new Scanner(System.in);
int num = sc.nextInt();
System.out.print("The reverse of the given number is: ");
//method calling
reverseNumber(num);
}
}
Output:
Enter the number that you want to reverse: 1413 The reverse of the given number is: 3141
More java programs:
Java Program to Print Multiplication Table of a Number
Java Program to Get Input from User
Java Program to Count Number of Digits in a Number