We now introduce C# programming. Most of the C# apps you’ll study in this course process information and display results. In this chapter, we introduce console apps, these input and output text in a console window, which in Windows is known as the Command Prompt.

We begin with several examples that simply display messages on the screen. We then demonstrate an app that obtains two numbers from a user, calculates their sum and displays the result. You’ll perform various arithmetic calculations and save the results for later use. The last example in this chapter demonstrates decision-making fundamentals by comparing numbers and displaying messages based on the comparison results.