Group
File Handling in C#
Objective
1. Check if a command line argument is provided for the file name.
2. If no argument is present, prompt the user to enter the file name.
3. Use a StreamReader to read the file and display its contents.
4. Handle cases where the file does not exist or can't be read.
Create a program to display all the contents of a text file on screen (note: you must use a StreamReader). The name of the file will be entered in the command line or (if there is no command line present) asked to the user by the program.
Example C# Exercise
Show C# Code
using System;
using System.IO;
class Program
{
static void Main(string[] args)
{
string fileName;
// Check if the file name is provided as a command line argument
if (args.Length > 0)
{
// Use the command line argument as the file name
fileName = args[0];
}
else
{
// If no argument is provided, prompt the user to enter the file name
Console.WriteLine("Enter the file name:");
fileName = Console.ReadLine();
}
// Try to open and read the file using StreamReader
try
{
// Create a StreamReader object to read the file
using (StreamReader reader = new StreamReader(fileName))
{
string line;
// Read the file line by line and display it on the screen
while ((line = reader.ReadLine()) != null)
{
Console.WriteLine(line);
}
}
}
catch (FileNotFoundException)
{
// Handle the case where the file is not found
Console.WriteLine("Error: The file was not found.");
}
catch (IOException ex)
{
// Handle other potential IO errors
Console.WriteLine($"Error reading the file: {ex.Message}");
}
}
}
Output
// Output of the code (if the file "example.txt" contains the following lines):
This is the first line of the file.
Here is the second line.
And here is the third line.
Enter the file name:
example.txt
This is the first line of the file.
Here is the second line.
And here is the third line.