Program to Reverse a Number and String in C#

Last updated on February 13th, 2024 at 09:52 pm

In this article, we’ll explore how to reverse a number and string in C# with clear code examples and detailed explanations. Understanding these fundamental concepts is crucial whether you’re an experienced developer or just starting. Let’s dive in.

Table of Contents

1 Reverse a Number in C# Using Arithmetic Operations
2 Reverse a Number in C# Using String Manipulation
3 Reverse a String in C#
4 Using the foreach loop to reverse a string in C#:
5 Reversing a String Using InBuilt Method in C#
- 5.1 Related

Reverse a Number in C# Using Arithmetic Operations

Here is the code sample showing how to reverse a number in C#.

We’ll create a simple C# program that takes an input number from the console and uses a while loop to reverse it using basic arithmetic operations.

using System;

namespace Reverse_Number_Program
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter a Number: ");
            int number = int.Parse(Console.ReadLine());
            int reminder, reverse = 0;


           // Loop until the original number becomes 0
            while (number > 0)
            {
              // Extract the last digit of the number (remainder when divided by 10)
                reminder = number % 10;

                 // Build the reversed number by multiplying the current reversed number by 10
                // and adding the extracted digit
                reverse = (reverse * 10) + reminder;


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

            Console.WriteLine($"The Reverse order is: {reverse}");
            Console.ReadKey();
        }
    }
}

Output:

Enter a Number: 12345
The Reverse order is: 54321

Reverse a Number in C# Using String Manipulation

using System;

class Program
{
    static void Main()
    {
        int number = 12345;
        string reversedNumberString = ReverseNumber(number);

        Console.WriteLine($"Original Number: {number}");
        Console.WriteLine($"Reversed Number: {reversedNumberString}");
    }

    static string ReverseNumber(int num)
    {
        char[] charArray = num.ToString().ToCharArray();
        Array.Reverse(charArray);
        return new string(charArray);
    }
}

Output:

Original Number: 12345
Reversed Number: 54321

Reverse a String in C#

Now, let’s tackle string reversal. We’ll take a string as input from the console and reverse it using a for loop.

Here’s the code to reverse a string in C#:

using System;

namespace Program_To_Revrse_String
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter a String: ");
            string name = Console.ReadLine();
            string reverse = string.Empty;

            for (int i = name.Length - 1; i >= 0; i--)
            {
                reverse += name[i];
            }

            Console.WriteLine($"The Reverse string is: {reverse}");
            Console.ReadKey();
        }
    }
}

Output:

Enter a String: Hello World
The Reverse string is: dlroW olleH

Code Explanation:

The program prompts the user to enter a string using Console.ReadLine() and stores it in the variable name.
The program uses a for loop to iterate through the characters of the input string in reverse order (from the last character to the first). It appends each character to the reverse string.
The reversed string is then displayed using Console.WriteLine().

Using the foreach loop to reverse a string in C#:

An alternative approach is to use a foreach loop to reverse a string in C#:

using System;

namespace ReverseNumberPrograms
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter a String: ");
            string name = Console.ReadLine();
            string reverse = string.Empty;

            foreach (char c in name)
            {
                reverse = c + reverse;
            }

            Console.WriteLine($"The Reverse string is: {reverse}");
            Console.ReadKey();
        }
    }
}

Output:

Enter a String: Hello World
The Reverse string is: dlroW olleH

Reversing a String Using InBuilt Method in C#

Lastly, let’s use the Array.Reverse method to reverse a string. We’ll convert the string to a character array, reverse its elements, and create a new string from the reversed array:

using System;

namespace ReverseString
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter a String: ");
            string name = Console.ReadLine();
            char[] nameArray = name.ToCharArray();
            Array.Reverse(nameArray);
            string reverse = new string(nameArray);

            Console.WriteLine($"The Reverse string is: {reverse}");
            Console.ReadKey();
        }
    }
}

Output:

Enter a String: Hello World
The Reverse string is: dlroW olleH

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Shekh Ali

Meet Sheikh Ali, a skilled Software engineer and passionate a blogger. He enjoys sharing his expertise in C#, Java, SQL, Design Patterns, and other related topics through his writing. When he's not coding, Sheikh Ali can often indulge in his passions for reading books and fitness training.

Reverse a Number in C# Using Arithmetic Operations

Reverse a Number in C# Using String Manipulation

Reverse a String in C#

Using the foreach loop to reverse a string in C#:

Reversing a String Using InBuilt Method in C#

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