C#: Create a new string where 'if' is added to the front of a given string

Last update on June 25 2025 13:03:15 (UTC/GMT +8 hours)

Add 'if' to String if Absent

Write a C# Sharp program to create a string where 'if' is added to the front of a given string. If the string already begins with 'if', return it unchanged.

Visual Presentation:

C# Sharp: Basic Algorithm Exercises - Create a new string where 'if' is added to the front of a given string.

Sample Solution:

C# Sharp Code:

using System;

// Namespace declaration
namespace exercises
{
    // Class declaration
    class Program
    {
        // Main method - entry point of the program
        static void Main(string[] args)
        {
            // Calling the 'test' method with different strings and displaying the returned values
            Console.WriteLine(test("if else"));   // Output: "if else"
            Console.WriteLine(test("else"));      // Output: "if else"
            Console.ReadLine();                   // Keeping the console window open
        }

        // Method to modify the string based on a condition
        public static string test(string s)
        {
            // Checking if the length of the string is greater than 2 and if the substring from index 0 to 1 is "if"
            if (s.Length > 2 && s.Substring(0, 2).Equals("if"))
            {
                return s;  // If the condition is true, return the original string 's'
            }
            return "if " + s;  // If the condition is false, prepend "if " to the string 's' and return it
        }
    }
}

Sample Output:

if else
if else

Flowchart:

For more Practice: Solve these Related Problems:

Write a C# program to add 'else' at the end of a string if it doesn’t already end with 'else'.
Write a C# program to add 'if' at both the beginning and end of the string only if it doesn’t start or end with it.
Write a C# program that checks if the string starts with 'if' and ends with 'then'; if not, adds them accordingly.
Write a C# program to insert 'if' at the second position of a string if it doesn’t already appear there.

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