C#: Reverse an integer and add with the original number

Last update on August 25 2025 12:50:20 (UTC/GMT +8 hours)

Write a C# Sharp program to reverse a positive integer and add the reversed number to the original number.

Sample Data:
(456) - > 456654
(-123) -> "Input a positive number."
(10000) -> 1000000001

Sample Solution-1:

C# Sharp Code:

using System;
using System.Linq;

namespace exercises
{
    class Program
    {
        static void Main(string[] args)
        {
            // Declare and initialize an integer variable
            int n = 567;

            // Display the original number
            Console.WriteLine("Original number: " + n);

            // Display the action about to be performed
            Console.WriteLine("Reverse the said integer and add with the original number-");

            // Invoke the 'test' method and display the result
            Console.WriteLine(test(n));

            // Change the value of n to a negative number
            n = -123;

            // Display the new original number
            Console.WriteLine("\nOriginal number: " + n);

            // Display the action about to be performed
            Console.WriteLine("Reverse the said integer and add with the original number-");

            // Invoke the 'test' method and display the result
            Console.WriteLine(test(n));

            // Change the value of n to a large number
            n = 10000;

            // Display the new original number
            Console.WriteLine("\nOriginal number: " + n);

            // Display the action about to be performed
            Console.WriteLine("Reverse the said integer and add with the original number-");

            // Invoke the 'test' method and display the result
            Console.WriteLine(test(n));
        }

        // Define a method 'test' that takes an integer argument 'n' and returns a string
        public static string test(int n)
        {
            // Check if the number is greater than zero
            if (n > 0)
            {
                // Convert the integer to a string, reverse it, convert back to string, and concatenate with the original number
                return n + new string(n.ToString().Reverse().ToArray());
            }
            // Return a message if the input is not a positive number
            return "Input a positive number.";
        }
    }
}

Sample Output:

Original number: 567
Reverse the said integer and add with the original number-
567765

Original number: -123
Reverse the said integer and add with the original number-
Input a positive number.

Original number: 10000
Reverse the said integer and add with the original number-
1000000001

Flowchart :

Sample Solution-2:

C# Sharp Code:

using System;
using System.Linq;

namespace exercises
{
    class Program
    {
        static void Main(string[] args)
        {
            // Declare and initialize an integer variable
            int n = 567;

            // Display the original number
            Console.WriteLine("Original number: " + n);

            // Display the action about to be performed
            Console.WriteLine("Reverse the said integer and add with the original number-");

            // Invoke the 'test' method and display the result
            Console.WriteLine(test(n));

            // Change the value of n to a negative number
            n = -123;

            // Display the new original number
            Console.WriteLine("\nOriginal number: " + n);

            // Display the action about to be performed
            Console.WriteLine("Reverse the said integer and add with the original number-");

            // Invoke the 'test' method and display the result
            Console.WriteLine(test(n));

            // Change the value of n to a large number
            n = 10000;

            // Display the new original number
            Console.WriteLine("\nOriginal number: " + n);

            // Display the action about to be performed
            Console.WriteLine("Reverse the said integer and add with the original number-");

            // Invoke the 'test' method and display the result
            Console.WriteLine(test(n));
        }

        // Define a method 'test' that takes an integer argument 'n' and returns a string
        public static string test(int n)
        {
            // Check if the number is greater than zero
            if (n > 0)
            {
                // Convert the integer to a string and concatenate it with its reverse
                return n.ToString() + string.Concat(n.ToString().Reverse());
            }
            // Return a message if the input is not a positive number
            return "Input a positive number.";
        }
    }
}

Sample Output:

Original number: 567
Reverse the said integer and add with the original number-
567765

Original number: -123
Reverse the said integer and add with the original number-
Input a positive number.

Original number: 10000
Reverse the said integer and add with the original number-
1000000001

Flowchart :

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C# Sharp Code Editor:

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