Handling Input/Output

Reading Input from the Console

Use Console.ReadLine() to accept input from the user:

Console.Write("Enter your name: ");
string name = Console.ReadLine();
Console.WriteLine($"Hello, {name}!");

Convert input to other types using parsing:

Console.Write("Enter your age: ");
int age = int.Parse(Console.ReadLine());

Writing Output to the Console

Use Console.WriteLine() and Console.Write() to display text:

• WriteLine – moves to the next line after printing
• Write – stays on the same line

Reading and Writing Text Files

Use System.IO namespace for file operations. Always handle exceptions for I/O safety.

Writing to a file:

using System.IO;

File.WriteAllText("message.txt", "This is a test message.");

Reading from a file:

string content = File.ReadAllText("message.txt");
Console.WriteLine(content);

Appending to a file:

File.AppendAllText("message.txt", "\nAppended line.");

Best Practices

• Always validate and sanitize user input
• Use TryParse instead of Parse to avoid exceptions
• Wrap file operations in try-catch blocks
• Use using blocks for streams and writers

Mastering input and output is essential for building interactive and file-based applications. In the next lesson, we’ll introduce Dependency Injection (IoC) and demonstrate how to use it in console apps for clean, testable code.