Write a code to reverse a number in Java, C, C++ and Python

Introduction:

        One of the classic programming challenges is reversing a number. This problem not only tests a coder's fundamental understanding but also their ability to think algorithmically across different programming languages. Below, we'll explore the solutions in C, C++, Java, and Python, but first, let's visualize what reversing a number means.

Visual Representation:

        Imagine the number is 7789. Reversing it would yield 9877. Let's break this process down to make it more digestible:

- Start with 7789 

- Extract the last digit (9) and add it to the reverse 

- Remove the last digit, leaving 778 

- Repeat until no digits are left 

- Result: 9877

                        

Solutions:

Now let us see the solution in different programming languages.

1. Java

        import java.util.Scanner;

        public class ReverseNumber {
            public static void main(String[] args) {
                Scanner scanner = new Scanner(System.in);
                System.out.print("Enter a number: ");

                // Reading the number from the user
                int n = scanner.nextInt();
                int reverse = 0;

                // Loop until all digits are processed
                while(n != 0) {
                    // Extract the last digit and add it to the reversed number
                    reverse = reverse * 10 + n % 10;

                    // Remove the last digit from the original number
                    n /= 10;
                }

                // Print the reversed number
                System.out.println("Reversed number = " + reverse);
            }

        }

2. Python

        # Reading the number from the user

        n = int(input("Enter a number: "))

        reverse = 0

        # Loop until all digits are processed

        while n != 0:

            # Extract the last digit and add it to the reversed number

            reverse = reverse * 10 + n % 10

            # Remove the last digit from the original number

            n //= 10

        # Print the reversed number

        print("Reversed number =", reverse)

3. C++

        #include <iostream>
        using namespace std;

        int main() {
            int n, reverse = 0;
            cout << "Enter a number: ";

            // Reading the number from the user
            cin >> n;

            // Loop until all digits are processed
            while(n != 0) {
                // Extract the last digit and add it to the reversed number
                reverse = reverse * 10 + n % 10;

                // Remove the last digit from the original number
                n /= 10;
            }

            // Print the reversed number
            cout << "Reversed number = " << reverse;
            return 0;

        }

4. C 

        #include <stdio.h>

        int main() {
            int n, reverse = 0;
            printf("Enter a number: ");

            // Reading the number from the user
            scanf("%d", &n);

            // Loop until all digits are processed
            while(n != 0) {
                // Extract the last digit and add it to the reversed number
                reverse = reverse * 10 + n % 10;

                // Remove the last digit from the original number
                n /= 10;
            }
    
            // Print the reversed number
            printf("Reversed number = %d", reverse);
            return 0;

        }

Conclusion:

        Reversing a number might seem straightforward, but it encapsulates key programming concepts such as loops and arithmetic operations. Regardless of the language, the approach remains the same: isolate digits, reconstruct in reverse order, and handle edge cases gracefully. 

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