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# Number is Palindrome or Not in C

Last Updated on May 31, 2023 by Mayank Dham In the realm of programming, solving problems related to numbers is an essential skill for any developer. One intriguing challenge involves identifying whether a given number is a palindrome or not. A palindrome number remains the same even when its digits are reversed, creating a symmetrical pattern. For example, 121, 777, and 5665 are all palindrome numbers.

In this article, we will explore the concept of palindrome numbers and provide a step-by-step guide on how to determine whether a number is a palindrome or not using the C programming language. We will delve into various approaches and algorithms, allowing both beginners and experienced programmers to gain a deeper understanding of this fascinating problem.

## How We can Check the Number is Palindrome or Not in C?

A number that remains the same after it is flipped around is known as a palindrome. Palindromes include the numbers 121, 34543, 343, 131, and 48984.
A number is said to be a palindrome if it reads the same forward as it does backward when its last digit is the same as the first digit, second digit is the same as the second-last digit, and so on. In conclusion, a number is a palindrome if the outcome of reversing its digits—reversing the sequence of the digits—is the same as the outcome of utilizing the original number.

### Algorithm for Number is Palindrome or Not in C

Let’s now examine the standard procedure for determining if a number is a palindrome or not:
Step 1. First, check to see if the user-provided integer N is a palindrome.
Step 2. Create a duplicate of the user-supplied number and assign it to a temporary variable (temp = N) in step two.
Step 3. In step 3, Create two new variables, digit and reverse, and set their initial values to represent, respectively, the number’s digits and reverse.
Step 4. Initialize a while loop in step four.
Step 5. Use the modulus operator in step 5 to eliminate the final digit from the specified integer (N%10).
Step 6. In step 6, After multiplying the past value of the reverse variable by 10, add this number to the reverse variable. The backward multiplied by 10 plus the digit equals the reverse.(Reverse: Reverse * 10 + digit)
Step 7. In step 7, In order to access the next digit from the left side, the variable n needs to be updated with a decrement statement. (n = n / 10)
Step 8. For step 8, Continue with steps 5 through 7 until N is more than zero (N>0).
Step 9. Step 9: Finish

## Dry Run of Palindrome Number in C

Let’s follow the values of these three variables for the input number 1991 during each iteration of the while loop to better understand how the iterative method for testing palindrome in C functions.
Initially:

• N = 1991
• Reverse = 0
• temp = 1991

Repetition 1:

• N = 199
• Reverse = 1
• temp = 1991

Repetition 2:

• N = 19
• Reverse = 19
• temp = 1991

Repetition 3:

• N = 1
• Reverse = 199
• temp = 1991

Repetition 4:

• N = 0
• Reverse = 1991
• temp = 1991

Here, we can see that a digit from the input number is subtracted and stored in the reverse variable after each iteration. Once all of the digits have been saved in the reverse variable in reverse order, the loop ends. To determine if the input number is a palindrome or not, the reversed number is compared to the number kept in the temporary variable.
As a result, after applying the aforementioned procedure, the reverse variable will retain the input number’s inverse, and the temp variable will hold the input number’s original value. Let’s see how this iterative approach to palindrome number verification may be applied in C.

Code Implementation

```#include <stdio.h>

int main()
{
int N=1991, digit, reverse = 0, temp;

temp = N;

//loop to find reverse number
while(temp != 0)
{
digit = temp % 10;
reverse = reverse * 10 + digit;
temp /= 10;
};

if (N == reverse)
printf("%d is Palindrome", N);
else
printf("%d is not a Palindrome", N);
}

```

Output:

``1991 is Palindrome``

To determine if a number is a palindrome or not, the input number 1991 is used. Iterative C is used by the program to determine whether a number is a palindrome. In this example, we can observe that reversing the number 1991 results in the same result: 1991, the original number. The program’s output reveals that the number 1991 is a palindrome.
There is one more method to check number is palindrome or not by Mathematical technique using recursion

## Mathematical Technique using Recursion For Number is Palindrome or Not in C Programming Language

We can also check if the number is palindrome or not using the recursive method.
In this, we can see that a digit from the input number is subtracted and stored in the reverse variable after each call. Once all of the digits have been saved in the reverse variable in reverse order, the loop ends. To determine if the input number is a palindrome or not, the reversed number is compared to the number kept in the temporary variable.

### Code Implementation

```#include

int ReverseNumber(int N, int rev){
if(N == 0)
return rev;

int rem = N % 10;
rev = rev * 10 + rem;

return ReverseNumber(N / 10, rev);
}

int main ()
{
int N, reverse = 0;
N=1991;

if (ReverseNumber(N, reverse) == N)
printf("%d is Palindrome", N);
else
printf("%d is not a Palindrome", N);
}
```

Output

``1991 is Palindrome``

Conclusion
In conclusion, determining whether a number is a palindrome or not in C is a fascinating problem that can be solved using various techniques and algorithms. Throughout this article, we explored different approaches to tackle this challenge, ranging from converting the number into a string and checking for symmetry to using mathematical operations to reverse and compare the digits.

We began by understanding the concept of palindrome numbers and their unique property of remaining the same when their digits are reversed. We then delved into practical implementations, presenting step-by-step explanations and C code examples.

By examining the different strategies, readers gained insights into fundamental programming concepts, such as loops, conditionals, and mathematical operations, while honing their problem-solving skills. Whether you are a beginner or an experienced programmer, the techniques discussed in this article provided a solid foundation for effectively detecting palindrome numbers in C.

## FAQ Related to Number is Palindrome or Not in C

Q1: Are there any built-in functions in C to check for palindrome numbers?
No, C does not have built-in functions specifically designed to check for palindrome numbers. However, you can use standard string manipulation functions to convert the number into a string and compare it with its reversed form.

Q2: What is the most efficient way to check for palindrome numbers in C?
The most efficient approach is to use mathematical operations to reverse the digits of the number and compare it with the original number. This avoids the overhead of converting the number into a string. By extracting and manipulating individual digits, you can determine whether a number is a palindrome or not in an optimized manner.

Q3: Can negative numbers be palindromes?
A: In the context of determining palindrome numbers, negative numbers are typically not considered palindromes. Since the negative sign is not part of the digit pattern, reversing the digits of a negative number will not yield the original number.

Q4: What are some practical applications of palindrome number detection in C?
A: Palindrome number detection in C can be applied in various practical scenarios. It is commonly used in algorithms that involve string manipulation, such as checking for palindromic words or phrases. Additionally, it can be useful in tasks that involve number manipulation and pattern recognition, such as number puzzles or validating data integrity.