C# program to replace all spaces in a string with %20

Here's a C# program that replaces all spaces in a string with "%20":

using System;

class Program
{
    static void Main()
    {
        string inputString = "Hello, World!";

        string replacedString = ReplaceSpaces(inputString);

        Console.WriteLine("String after replacing spaces: " + replacedString);
    }

    static string ReplaceSpaces(string inputString)
    {
        // Replace spaces with "%20"
        string replacedString = inputString.Replace(" ", "%20");

        return replacedString;
    }
}

In this program, we have the 'ReplaceSpaces' method that takes a string as input and returns a new string where all spaces have been replaced with "%20".

We use the 'Replace' method of the 'string' class to replace all occurrences of the space character (" ") with "%20". The 'Replace' method returns a new string with the replacements made.

Finally, we return the replaced string.

String after replacing spaces: Hello,%20World!

The spaces in the input string "Hello, World!" have been replaced with "%20".