C To C# Converter - C# Programming Exercise

// Import necessary namespaces
using System; // System namespace for basic input/output and file handling
using System.IO; // File handling functions (read/write)
using System.Text.RegularExpressions; // Regex operations for pattern matching and replacements

class CToCSharpConverter // Define the CToCSharpConverter class that will handle the conversion
{
    static void Main(string[] args) // Entry point of the program
    {
        // Ensure the user has provided a file to convert
        if (args.Length != 1) // Check if no file path is provided
        {
            Console.WriteLine("Usage: CToCSharpConverter "); // Inform the user about the correct usage
            return; // Exit the program if the file argument is missing
        }

        string inputFilePath = args[0]; // Store the input file path provided by the user

        // Check if the provided file exists
        if (!File.Exists(inputFilePath)) // Check if the input file doesn't exist
        {
            Console.WriteLine("Error: The C file does not exist."); // Notify the user about the missing file
            return; // Exit the program if the file does not exist
        }

        try
        {
            // Read the contents of the C file
            string cCode = File.ReadAllText(inputFilePath); // Read the entire content of the input file

            // Convert the C code to C# by applying transformations
            string cSharpCode = ConvertCToCSharp(cCode); // Call the method to convert C code to C#

            // Generate the C# file path (changing the file extension from .c to .cs)
            string outputFilePath = Path.ChangeExtension(inputFilePath, ".cs"); // Modify the file path to have a .cs extension

            // Write the converted C# code to the output file
            File.WriteAllText(outputFilePath, cSharpCode); // Save the converted C# code into a new file

            Console.WriteLine($"Conversion complete. C# code saved to {outputFilePath}"); // Inform the user about the successful conversion
        }
        catch (Exception ex) // Catch any exceptions that occur during the file reading or writing process
        {
            Console.WriteLine($"An error occurred: {ex.Message}"); // Print the error message if something goes wrong
        }
    }

    static string ConvertCToCSharp(string cCode) // Method to convert C code to C# code
    {
        // Convert includes to C# using 'using' keyword
        cCode = Regex.Replace(cCode, @"#include\s+<([^>]+)>", "using $1;"); // Replace #include statements with C# using statements

        // Convert 'int main()' to 'static void Main()' for the entry point
        cCode = Regex.Replace(cCode, @"\bint\s+main\s*\(\)\s*{", "static void Main() {"); // Change C's main to C#'s static Main

        // Convert 'printf' to 'Console.WriteLine'
        cCode = Regex.Replace(cCode, @"printf\s*\(([^)]+)\);", "Console.WriteLine($1);"); // Replace printf statements with Console.WriteLine

        // Handle 'return 0;' to remove it as it's not needed in C#
        cCode = Regex.Replace(cCode, @"\breturn\s+0\s*;", ""); // Remove return 0; as it is not necessary in C#

        // Add 'using System;' at the beginning for Console.WriteLine
        if (!cCode.Contains("using System;")) // Check if the using System; statement is already included
        {
            cCode = "using System;\n\n" + cCode; // Add 'using System;' at the start of the code if it's missing
        }

        // Handle other basic conversions (e.g., char to string, int to int, etc.)
        // For now, let's just handle basic `printf` to `Console.WriteLine` and main conversion.

        return cCode; // Return the converted C# code
    }
}