EXERCISES SECTION 2.2.2

Exercise 2.11: Explain whether each of the following is a declaration or a definition:

(a) extern int ix = 1024;

(b) int iy;

(c) extern int iz;

KEY CONCEPT: STATIC TYPING

C++(www.cppentry.com) is a statically typed language, which means that types are checked at compile time. The process by which types are checked is referred to as type checking.

As we’ve seen, the type of an object constrains the operations that the object can perform. In C++(www.cppentry.com), the compiler checks whether the operations we write are supported by the types we use. If we try to do things that the type does not support, the compiler generates an error message and does not produce an executable file.

As our programs get more complicated, we’ll see that static type checking can help find bugs. However, a consequence of static checking is that the type of every entity we use must be known to the compiler. As one example, we must declare the type of a variable before we can use that variable.