C++ Program to Check Whether a Number is Palindrome or Not

In this post, you will learn how to Check Whether a Number is Palindrome or Not using C++ programming language.

This lesson will teach you how to check whether a number is Palindrome or Not, with a do-while loop, assignment  operator, decision making statement and mathematical functions using the C++ Language. Let’s look at the below source code.

How to Check Whether a Number is Palindrome or Not?

Source Code

#include <iostream>
using namespace std;
int main()
{
     int n, num, digit, rev = 0;
     cin >> num;
     cout << "Enter a positive number: "<<num<<endl;
     n = num;
     do
     {
         digit = num % 10;
         rev = (rev * 10) + digit;
         num = num / 10;
     } 
     while (num != 0);
     cout << "The reverse of the number is: " << rev << endl;
     if (n == rev)
         cout << "\nThe number is a palindrome.";
     else
         cout << "\nThe number is not a palindrome.";
    return 0;
}

Input

12321

Output

Enter a positive number: 12321
The reverse of the number is: 12321
The number is a palindrome.

The statements #include<iostream>, using namespace std, int main are the main factors that support the function of the source code. Now we can look into the working and layout of the code’s function.

1. A palindrome number is a number that is same after reverse. For example 121, 34543, 343, 131, 48984 are the palindrome numbers.
2. Declare the variables n, num, digit, rev as variables and initialize the rev value as o.
3. Collect the values from the user and store it in the integer values using function cin>>  and display the values using cout<< and the Insertion Operators'<<‘ , ‘>>’.
4. Assign n = num using the assignment operator and create a do while loop with the condition where the value of n is not equal to 0.
5. In the do while loop the loop statement is executed once first and then the condition is verified. The loop is executed multiple times until the condition is not satisfied.
6. In the loop statement first we find the reminder of num and 10 and store the value in digit, next we execute the mathematical expression rev = (rev * 10) + digit followed by the mathematical expression num = num / 10
7. After the calculation the answer is displayed, then using the if else statement we declare the condition to compare the the initial number and the calculated number.
8. According to the comparison, the respective output statement is displayed, whether the number is palindrome or not.
9. The output statement is displayed and the execution is terminated.

Note: The ‘ << endl ‘ in the code is used to end the current line and move to the next line and ‘\n’ is also a new line function, to understand how both the functions work exclude it from the code, move it around and work with it.