C#: Create and write some line of text which does not contain a given string in a line

using System; // Importing the System namespace for basic functionalities
using System.IO; // Importing the System.IO namespace for file operations

class WriteTextFile // Declaring a class named WriteTextFile
{
    static void Main() // Declaring the Main method
    {
        string fileName = @"mytest.txt"; // Initializing a string variable with the file name
        string[] ArrLines; // Declaring a string array variable to store lines of text
        string str; // Declaring a string variable for input string to ignore
        int n, i; // Declaring variables for counting lines and iterating

        Console.Write("\n\n Create and write some line of text which does not contain a given string in a line  :\n"); // Displaying a message in the console
        Console.Write("------------------------------------------------------------------------------------------\n");

        if (File.Exists(fileName)) // Checking if the file already exists and deleting it if true
        {
            File.Delete(fileName); // Deleting the file if it exists
        }

        Console.Write(" Input the string to ignore the line : "); // Prompting the user to input a string
        str = Console.ReadLine(); // Reading the string to ignore

        Console.Write(" Input number of lines to write in the file  : "); // Prompting the user to input the number of lines
        n = Convert.ToInt32(Console.ReadLine()); // Reading the number of lines provided by the user
        ArrLines = new string[n]; // Initializing the string array with the provided number of lines

        Console.Write(" Input {0} strings below :\n", n); // Prompting the user to input the lines of text

        // Loop to input lines of text based on the user-defined count
        for (i = 0; i < n; i++)
        {
            Console.Write(" Input line {0} : ", i + 1); // Prompting for each line
            ArrLines[i] = Console.ReadLine(); // Reading and storing each line of text in the array
        }

        // Writing lines to the file, excluding those containing the given string to ignore
        using (System.IO.StreamWriter file = new System.IO.StreamWriter(@"mytest.txt"))
        {
            foreach (string line in ArrLines)
            {
                if (!line.Contains(str)) // Writing the line to the file if it doesn't contain the specified string
                {
                    file.WriteLine(line);
                }
            }
        }

        using (StreamReader sr = File.OpenText(fileName)) // Opening a StreamReader to read the content of the file
        {
            string s = "";
            Console.Write("\n The line has been ignored if it contains the string '{0}'. \n", str); // Displaying a message about ignored lines
            Console.Write("\n The content of the file is  :\n"); // Displaying a message
            Console.Write("----------------------------------\n");

            // Reading and displaying each line of the file
            while ((s = sr.ReadLine()) != null) // Looping through each line until the end of the file
            {
                Console.WriteLine(" {0} ", s); // Displaying each line in the console
            }
            Console.WriteLine(); // Adding a newline for formatting
        }
    }
}