Chapter 2. Variables and Basic Types

Contents

• Section 2.1 Primitive Built-in Types
• Section 2.2 Variables
• Section 2.3 Compound Types
• Section 2.4 const Qualifier
• Section 2.5 Dealing with Types
• Section 2.6 Defining Our Own Data Structures
• Chapter Summary
• Defined Terms

Types are fundamental to any program: They tell us what our data mean and what operations we can perform on those data.

C++ has extensive support for types. The language defines several primitive types (characters, integers, floating-point numbers, etc.) and provides mechanisms that let us define our own data types. The library uses these mechanisms to define more complicated types such as variable-length character strings, vectors, and so on. This chapter covers the built-in types and begins our coverage of how C++ supports more complicated types.

Types determine the meaning of the data and operations in our programs. The meaning of even as simple a statement as

i = i + j;

depends on the types of i and j. If i and j are integers, this statement has the ordinary, arithmetic meaning of +. However, if i and j are Sales_item objects (§ 1.5.1, p. 20), this statement adds the components of these two objects.