C Primer Plus®, Third Edition

typedef: A Quick Look

The typedef function is an advanced data feature that enables you to create your own name for a type. It is similar to #define in that respect, but with three differences:

• Unlike #define, typedef is limited to giving symbolic names to types only and not to values.

• The typedef function is performed by the compiler, not the preprocessor.

• Within its limits, typedef is more flexible than #define.

Let's see how typedef works. Suppose you want to use the term BYTE for one-byte numbers. You simply define BYTE as if it were a char variable and precede the definition by the keyword typedef.

typedef unsigned char BYTE;

From then on, you can use BYTE to define variables:

BYTE x, y[10], * z;

The scope of this definition depends on ...