C#: Read the first line from a file

Last update on December 20 2024 12:49:36 (UTC/GMT +8 hours)

Write a C# Sharp program to read the first line of a file.

Sample Solution:-

C# Sharp Code:

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

class filexercise11 // Declaring a class named filexercise11
{
    public static void Main() // Declaring the Main method
    {
        string fileName = @"mytest.txt"; // Initializing a string variable with the file name

        try // Starting a try-catch block to handle exceptions
        {
            // Delete the file if it exists.
            if (File.Exists(fileName)) // Checking if the file exists and deleting it if true
            {
                File.Delete(fileName); // Deleting the file if it exists
            }
	
	        // Displaying a message to read the first line from a file
	        Console.Write("\n\n Read the first line from a file  :\n");
		    Console.Write("---------------------------------------\n");
		
            // Create the file and write some lines of text to it.
            using (StreamWriter fileStr = File.CreateText(fileName)) // Creating a StreamWriter to write text to the file
            {
                fileStr.WriteLine(" test line 1"); // Writing line 1 to the file
                fileStr.WriteLine(" test line 2"); // Writing line 2 to the file
                fileStr.WriteLine(" Test line 3"); // Writing line 3 to the file
            }	

            // Displaying the content of the file
            using (StreamReader sr = File.OpenText(fileName)) // Opening a StreamReader to read the content of the file
            {
                string s = "";
                Console.WriteLine(" Here is the content of the file mytest.txt : ");
                while ((s = sr.ReadLine()) != null) // Looping through each line until the end of the file
                {
                    Console.WriteLine(s); // Displaying each line in the console
                }
                Console.WriteLine("");
            }

            // Displaying the content of the first line of the file
            Console.Write("\n The content of the first line of the file is :\n");
            if (File.Exists(fileName)) // Checking if the file exists
            {
                string[] lines = File.ReadAllLines(fileName); // Reading all lines from the file
                Console.Write(lines[0]); // Writing the first line of the file to the console
            }        
            Console.WriteLine(); 
        }
        catch (Exception MyExcep) // Catching and handling exceptions
        {
            Console.WriteLine(MyExcep.ToString()); // Displaying exception details in case of error
        }
    }
}

Sample Output:

Read the first line from a file  :                                                                           
---------------------------------------                                                                       
 Here is the content of the file mytest.txt :                                                                 
 test line 1                                                                                                  
 test line 2                                                                                                  
 Test line 3                                                                                                  
   
 The content of the first line of the file is :                                                               
 test line 1 
 

Flowchart :

C# Sharp Code Editor:

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