Java program to reverse a number using loops

In this article, we will discuss the concept of the Java program to reverse a number using loops.

In this post, we are going to learn how to find reverse number of the given number in Java programming language

Reversed number

Java code to reverse a number using for loop

Program 1

The program allows the user to enter a number and it displays the reversed pattern of the given number using for loop in Java language

when you are entered 34567,
The output will be displayed as 76543

import java.util.Scanner;
class Reversed_Num{
public static void main(String args[]){
int num,reversed_Num=0;
Scanner scan=new Scanner(System.in);
//This statements takes input from theuser
System.out.print("Enter the number for find reverse: ");
//get input and it is stored num variable
num=scan.nextInt();
for( ; num!=0;){
reversed_Num=reversed_Num*10;
reversed_Num=reversed_Num+num%10;
num=num/10;
}
System.out.print("Reversed number of given number is: "+reversed_Num);
}
}

When the above program is executed, it produces the following result

Program 1

Explanation

Declare and initialize two variables as follows int num,reversed_Num=0;
The user is asked to enter a number and it is stored in the integer variable of ‘num‘
The for loop is used to create the reversed number of the given number
The for loop is functioning until ‘ num‘ is not equal to zero
Finally, the output is displayed as the reversed number

Java code to reverse a number using while loop

Program 1

The program allows the user to enter a number and it displays the reverse pattern of the given number using while loop in Java language

when you are entered 12345,
The output will be displayed as 54321 using the program

import java.util.Scanner;
class Reversed_NumWhile{
public static void main(String args[]){
int num,rem,reversed_Num=0;
Scanner scan=new Scanner(System.in);
//This statements takes input from theuser
System.out.print("Enter the number for find reverse: ");
//get input and it is stored num variable
num=scan.nextInt();
while(num>0){
    rem=num%10;
    reversed_Num=reversed_Num*10+rem;
    num=num/10;
}
System.out.print("You entered : "+num);
System.out.print("Reverse of the number is: "+reversed_Num);
}
}

When the above program is executed, it produces the following result

Program 2

Explanation

Declare and initialize three variables as follows int num,rem,reversed_Num=0;
The user is asked to enter a number and it is stored in the integer variable of ‘num’
The while loop is used to create the reversed number of the given number
The while loop is functioning until ‘ num‘ is greater than zero
Finally, the output is displayed as the reversed number

Java code to reverse a number using do-while loop

Program 3

The program allows the user to enter a number and it displays the reverse pattern of the given number using do-while loop in Java language

when you are entered 56789,
The output will be displayed as 98765 using the program

import java.util.Scanner;
class Reversed_NumDoWhile{
public static void main(String args[]){
int num,rem,reversed_Num=0;
Scanner scan=new Scanner(System.in);
//This statements takes input from theuser
System.out.print("Enter the number for find reverse: ");
//get input and it is stored num variable
num=scan.nextInt();
do{
    rem=num%10;
    reversed_Num=reversed_Num*10+rem;
    num=num/10;
}while(num>0);
System.out.print("You entered : "+num);
System.out.print("Reverse of the number is: "+reversed_Num);
}
}

When the above program is executed, it produces the following result

Program 3

Explanation

Declare and initialize three variables as follows int num,rem,reversed_Num=0;
The user is asked to enter a number and it is stored in the integer variable of ‘num’
The do-while loop is used to create the reversed number of the given number
The do-while loop is functioning until ‘ num‘ is greater than zero
Finally, the output is displayed as the reversed number