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System.Console (Input)

The keyboard is the standard input device in C#, and the System.Console class provides the method Console.ReadLine() for reading user input.

When Console.ReadLine() is called, the system waits for the user to type something on the keyboard. The entered data can be assigned to a variable or ignored:

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Console.WriteLine("Enter your name: ");
string name = Console.ReadLine();               // Data entered is assigned to a variable
Console.WriteLine($"Hello {name}");
Console.WriteLine("Press any key to quit...");
Console.ReadLine();                             // Data entered is ignored

Data entered through the keyboard is always treated as a string. If you need the data to be numeric, it must be converted before any processing can be performed. As mentioned earlier, there are two common approaches for this conversion:

  • Using int.Parse() or int.TryParse()
  • Using Convert.ToInt32()

If you're reading data from a trusted source (e.g., when you expect to read an integer), using Parse() is generally safe. However, if you're getting the data from a user, it's advisable to use TryParse() to avoid exceptions.

Here are examples of both methods for reading numeric input:

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Console.WriteLine("Enter your age: ");
int age = int.Parse(Console.ReadLine()); // Using Parse

// or

Console.Write("Enter your age: ");
int age1 = Convert.ToInt32(Console.ReadLine()); // Using Convert

Note

There is very little difference in behavior between Convert and Parse(). However, it's worth mentioning that Convert.ToInt32() will return 0 if the argument is null.

Be aware that exception errors may still occur during conversion and should be handled appropriately.

If you're only expecting a single key to be input (for example, when displaying a prompt like "Press any key to continue..."), you can use Console.ReadKey() instead:

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Console.WriteLine("Press any key to continue...");
Console.ReadKey(); // Waits for a key press