C#: Create a new string taking the first character from a given string and the last character from another given string

Last update on June 27 2025 13:06:25 (UTC/GMT +8 hours)

First and Last Char of Two Strings

Write a C# Sharp program to create a string by taking the first character from a string and the last character from another string. If a string's length is 0, use '#' as its missing character.

Visual Presentation:

Sample Solution:-

C# Sharp Code:

using System; // Importing the System namespace

namespace exercises // Defining a namespace called 'exercises'
{
    class Program // Defining a class named 'Program'
    {
        static void Main(string[] args) // The entry point of the program
        {
            // Output the results of the test function with different strings as arguments
            Console.WriteLine(test("Hello", "Hi")); // Pass "Hello" and "Hi" as arguments to the test function
            Console.WriteLine(test("Python", "PHP")); // Pass "Python" and "PHP" as arguments to the test function
            Console.WriteLine(test("JS", "JS")); // Pass "JS" and "JS" as arguments to the test function
            Console.WriteLine(test("Csharp", "")); // Pass "Csharp" and an empty string as arguments to the test function
            Console.ReadLine(); // Wait for user input before closing the console window
        }

        // Function definition of the test function that takes two strings 's1' and 's2' and returns a string
        public static string test(string s1, string s2)
        {
            string lastChars = String.Empty; // Initialize an empty string 'lastChars'

            if (s1.Length > 0) // Check if the length of 's1' is greater than 0
            {
                lastChars += s1.Substring(0, 1); // If so, append the first character of 's1' to 'lastChars'
            }
            else
            {
                lastChars += "#"; // If 's1' is empty, append "#" to 'lastChars'
            }

            if (s2.Length > 0) // Check if the length of 's2' is greater than 0
            {
                lastChars += s2.Substring(s2.Length - 1); // If so, append the last character of 's2' to 'lastChars'
            }
            else
            {
                lastChars += "#"; // If 's2' is empty, append "#" to 'lastChars'
            }

            return lastChars; // Return the concatenated string 'lastChars'
        }
    }
}

Sample Output:

Hi
PP
JS
C#

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