# Reverse number in C using function

In this blog, weâ€™ll delve into reversing number in C using a function. Our previous blogs covered reversing numbers in C using different methods like for loops and while loops. Now, weâ€™ll focus on understanding the process of reversing numbers using a function in C. Letâ€™s dive in!

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## Sample code of reverse number in C using function

You can better grasp the idea by looking at the sample C program that reverses a number using the function that is provided below:

```//include necessary header files
#include <stdio.h>

//function to reverse a given number
int reverseNumber(int num) {
int reversedNum = 0, remainder;

//loop to extract each digit from the given number
while (num != 0) {
remainder = num % 10; //extract the last digit
reversedNum = reversedNum * 10 + remainder; //add the digit to the reversed number
num /= 10; //remove the last digit from the given number
}

return reversedNum; //return the reversed number
}

//main function
int main() {
int num, reversedNum;

//get input from user
printf("Enter a number: ");
scanf("%d", &num);

//call the reverseNumber function and store the returned value in reversedNum variable
reversedNum = reverseNumber(num);

//print the reversed number
printf("Reversed number: %d", reversedNum);

return 0;
}```

Explanation of the code:

1. Include Necessary Header Files: We include the `<stdio.h>` header file, which contains functions for input and output operations.

2. Function to Reverse a Given Number: The `reverseNumber` function takes an integer `num` as input and returns an integer, which is the reversed number. Inside the function:

Â Â Â â€“ We declare two integer variables: `reversedNum` to store the reversed number and `remainder` to store the remainder of the division operation.

Â Â Â â€“ Using a while loop, we extract each digit from the given number `num` until `num` becomes 0.

Â Â Â â€“ In each iteration of the loop:

Â Â Â Â Â â€“ We calculate the remainder by performing the modulus operation `%` with 10, which gives us the last digit of `num`.

Â Â Â Â Â â€“ After that we update the `reversedNum` by multiplying it by 10 and adding the extracted digit (`remainder`).

Â Â Â Â Â â€“ We remove the last digit from `num` by performing integer division with 10.

Â Â Â â€“ After the loop, we return the `reversedNum`.

3. Main Function:

Â Â Â â€“ We declare two integer variables `num` and `reversedNum`.

Â Â Â â€“ then we prompt the user to enter a number using the `printf` function.

Â Â Â â€“ We read the input number using the `scanf` function and store it in the `num` variable.

Â Â Â â€“ We call the `reverseNumber` function with the input number `num` as argument and store the returned reversed number in the `reversedNum` variable.

Â Â Â â€“ Finally, we print the reversed number using the `printf` function.

Learn How to reverse number in C using while loop Here!

#### Output:

``Enter a number: 123456789Reversed number: 987654321``

## Real-world Application of Reverse number in c using function

Reverse number operations in C are crucial in algorithmic tasks and practical applications, with real-world scenarios proving invaluable due to their fundamental role in various domains:

1. Cryptography uses numbers as keys or seeds to generate cryptographic hashes or pseudorandom numbers, enhancing security, and reversing numbers is crucial for encryption and decryption algorithms.

2. Reversing numbers aids in data validation and verification processes, detecting errors during input or transmission of sensitive information like credit card numbers or identification codes.

3. Numeric palindrome identification is crucial in systems with symmetric patterns or valid dates, such as date validation algorithms or date parsing operations.

4. Reverse number operations are utilized in numerical analysis for root finding and optimization tasks, often in Newtonâ€™s method or gradient descent for convergent solutions.

5. Also, reversing numbers allows for various mathematical operations and conversions, such as converting between numeral systems like binary, decimal, or hexadecimal, and performing arithmetic operations on individual digits.

6. Reversing numbers is crucial in text processing tasks, especially in formatting or parsing data from text-based files or documents, such as reverse engineering numeric patterns in log files or databases.

7. Reverse number operations are crucial in game development and puzzle-solving, improving game mechanics, challenges, and cryptographic puzzles for players to solve.

8. Reverse number operations are utilized in numerical representation tasks, such as creating unique identifiers or generating numeric sequences in sequences and series problems.

9. In database management systems, reversing numbers can be useful for sorting and indexing operations, facilitating efficient data retrieval and manipulation tasks.

10. In digital signal processing applications, reversing numbers can be employed in signal analysis and transformation algorithms, aiding in tasks like signal reconstruction or spectrum analysis.

We hope our blog helped you understand that reverse numbers in C using functions is a fundamental skill that enhances problem-solving abilities. Harness the wealth of programming resources on Newtum to elevate your skills and embark on a fulfilling coding journey.

## Reverse number in C using function- FAQ

1. What is the purpose of reversing a number in C using a function?

Answer â€“ Reversing a number allows for various applications such as cryptography, data validation, and numerical analysis.

2. How does the reverseNumber function work in the provided C code?

Answer â€“ The reverse number function iteratively extracts digits from the input number and constructs the reversed number.

3. Can I use the provided code to reverse negative numbers?

Answer- Yes, the code handles negative numbers by reversing the absolute value and preserving the sign.

4. Are there limitations to the size of the number that can be reversed using this function?

Answer- The function can reverse numbers within the integer range supported by the system.

5. What are the benefits of using a function to reverse numbers in C compared to other methods?

Answer â€“ Using a function promotes code reusability, readability, and modularity, making the program easier to maintain and understand.