2. Variables & Types

Programs store and transform data. This chapter introduces the fundamental building blocks: naming and storing values, the types those values can have, how to compute with them, and how to read input and display results.

Why this chapter matters

Everything a program does involves data. Before you can write useful programs you must understand:

• how variables hold values in memory

• what types C# offers and when each is appropriate

• how arithmetic and string operations work

• how to interact with the user through the console

Learning goals

By the end of this chapter, you should be able to:

• declare and initialize variables of numeric, boolean, and string types

• apply arithmetic and string operators correctly

• convert between types safely using casting and Parse

• read user input with Console.ReadLine and display results with Console.WriteLine

Chapter flow

• 2.1. Variables
• 2.2. Types
• 2.3. Operators
• 2.4. Input and Output
• 2.5. Preview Questions
• 2.6. Lab 02
• 2.7. Chapter Review