Reverse a String Using Linq

In C#, there are several ways to reverse a string. One of the simplest and most straightforward methods is to use the Array.Reverse method in conjunction with the ToCharArray method of the string.

Here is an example:

using System;

namespace ReverseString
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(ReverseString("Hello World!"));
        }

        static string ReverseString(string input)
        {
            char[] charArray = input.ToCharArray();
            Array.Reverse(charArray);
            return new string(charArray);
        }
    }
}

This program takes a string as input and returns the reversed string. The ToCharArray method converts the string into an array of characters and Array.Reverse reverses the elements in the array. Finally, the reversed character array is converted back into a string using the new string constructor.

Output for Reverse String

!dlroW olleH

Unit test cases for Reverse String in C#

You can add unit tests to your code to ensure that your ReverseString method is working correctly. Here is an example using the Assert class from the Microsoft.VisualStudio.TestTools.UnitTesting namespace:

using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;

namespace ReverseString.Tests
{
    [TestClass]
    public class ReverseStringTests
    {
        [TestMethod]
        public void ReverseString_WithHelloWorld_ReturnsDLROWOLLEH()
        {
            // Arrange
            string input = "Hello World";

            // Act
            string result = ReverseString.Program.ReverseString(input);

            // Assert
            Assert.AreEqual("DLROW OLLEH", result);
        }

        [TestMethod]
        public void ReverseString_WithEmptyString_ReturnsEmptyString()
        {
            // Arrange
            string input = "";

            // Act
            string result = ReverseString.Program.ReverseString(input);

            // Assert
            Assert.AreEqual("", result);
        }

        [TestMethod]
        public void ReverseString_WithSingleCharacter_ReturnsSameCharacter()
        {
            // Arrange
            string input = "a";

            // Act
            string result = ReverseString.Program.ReverseString(input);

            // Assert
            Assert.AreEqual("a", result);
        }

        [TestMethod]
        public void ReverseString_WithNumbers_ReturnsReversedNumbers()
        {
            // Arrange
            string input = "12345";

            // Act
            string result = ReverseString.Program.ReverseString(input);

            // Assert
            Assert.AreEqual("54321", result);
        }
    }
}

These tests will check that your ReverseString method returns the correct result for different inputs, including an empty string, a string with a single character, a string with numbers, and a string with letters and spaces.

Conclusion

In conclusion, reversing a string in C# can be done easily using the Array.Reverse method and the ToCharArray method of the string. It’s always a good practice to add unit tests to your code to ensure that it’s working correctly and to catch any issues early on.