C#: Copy one string into another string

using System;

// Define the Exercise8 class
public class Exercise8  
{  
    // Main method - entry point of the program
    public static void Main() 
    {
        string str1; // Declare a string variable to hold user input
        int i, l; // Declare variables for iteration and length

        // Prompt the user to input a string
        Console.Write("\n\nCopy one string into another string:\n");
        Console.Write("-----------------------------------------\n"); 	
        Console.Write("Input the string: ");
        str1 = Console.ReadLine(); // Read the input string from the user

        l = str1.Length; // Get the length of the input string
        string[] str2 = new string[l]; // Initialize an array to hold characters from the string

        // Copy each character from str1 to str2 character by character
        i = 0; // Initialize the iteration variable
        while (i < l)
        {
            string tmp = str1[i].ToString(); // Convert the character to a string
            str2[i] = tmp; // Copy the character to the str2 array
            i++; // Move to the next character
        }

        // Display the original string (str1), copied string (str2), and the number of characters copied
        Console.Write("\nThe First string is: {0}\n", str1);
        Console.Write("The Second string is: {0}\n", string.Join("", str2)); // Join characters in str2 to form a string
        Console.Write("Number of characters copied: {0}\n\n", i); // Display the number of characters copied
    }
}