Write a program to reverse a number

What is reverse number?

As number are 'reversed number' they swap places. (eg. 41 to 14)

Algorithm of a reverse number

Step 1: Read input(n)

Step 2: SET sum = 0, temp = n

Step 3: REPEAT Step 4 and Step 5 while(temp != 0)

Step 4: sum = (sum * 10) + (temp % 10)

Step 5: temp = temp/10 (REMOVE the last digit of the number)

Step 6: PRINT the REVERSE NUMBER

Step 7: Exit

Reverse a number in c programming

#include <stdio.h>
int main()
{
    int n, reverse = 0;
    printf("Enter the number : ");
    scanf("%d", &n);
    int temp = n;
    while(temp!=0){
        reverse = (reverse*10) + (temp%10);
        temp = temp / 10;
    }
    printf("Reverse of %d is : %d", n, sum);
    return 0;
}

This program takes input from the user. Then the while loop is start until the (temp !=0) is false.

In each iteration of the loop,

Let's see, n = 234 , temp = n = 234

Step 1: Initially temp is 234, check the condition (234!=0), condition true, now reverse = (0*10) + (234%10) = 0 + 4 = 4. Reverse 4, temp = temp / 10 = 234 / 10 = 23. temp = 23.

Step 2: Now temp is 23, check the condition (23!=0), condition true, now reverse = (4*10) + (23%10) = 40 + 3 = 43. Reverse 43, temp = temp / 10 = 23 / 10 = 2. temp = 2.

Step 3: Now temp is 2, check the condition (2 != 0), condition true, now reverse = (43 * 10) + (2 % 10) = 430 + 2 = 432. Reverse 432, temp = temp / 10 = 2 / 10 = 0. temp = 0.

Step 4: Now temp is 0, check the condition (0!=0), condition false, now the loop is terminated.

Finally, the reverse variable (which contains the reversed number) is print on the terminal.

C++ program to reverse a number

#include <iostream>
using namespace std;
int main()
{
    int n, reverse = 0;
    cout<<"Enter the number : ";
    cin>>n;
    int temp = n;
    
    while(temp!=0){
        reverse = (reverse*10) + (temp%10);
        temp = temp / 10;
    }
    
    cout<<"Reverse of "<<n<<" is : "<<reverse;
    return 0;
}

Output:

Enter the number : 7293
Reverse of 7293 is : 3927