Interacting with the Console

When writing applications that interact with a user the simplest method is using a console application. In these applications, we can output information to the user and read strings of information from the user. All completed in the same console used to launch our application.

What would this look like?

Here is an example of the input and output of the code we are going to write:

Sending information to the console

All of the code we are going to use begins with Console and as the name suggests this is the part of C# that allows us to interact with the user.

Let's start with outputting a message to our user:

Console.WriteLine("Welcome to my program");

This writes a line of output to the console and returns the cursor to the beginning of the next line.

We can also include blank lines by using the special sequence \n which represents a blank line of its own.

The following will output two blank lines, one for the WriteLine and one because we included a \n

Console.WriteLine("\n");

The next method to discuss is a modification of Console.WriteLine. If we want to output some text but leave the cursor on the current line we can use Write instead of WriteLine. Write works the same way but does not move the cursor to the next line.

Console.Write("What is your name? ");

This code will print the prompt, the ?, and a blank space, leaving the cursor on the same line. This is a good experience for the user since it places the cursor on the same line.

Reading information from the console

Next we want to read information from the console. To read information we use Console.ReadLine. This will return a string which we can put into a variable.

var name = Console.ReadLine();

This will read a line of input (which the user ends by pressing return) and place the resulting string into the variable name.

Finally we print out the greeting with:

Console.WriteLine($"It is a pleasure to meet you, {name}");

Full program

using System;
namespace OurDotNetApp
{
  class Program
  {
    static void Main(string[] args)
    {
      Console.WriteLine("Welcome to my program");
      Console.WriteLine("\n");
      Console.Write("What is your name? ");
      var name = Console.ReadLine();
      Console.WriteLine($"It is a pleasure to meet you, {name}");
    }
  }
}