C Primer Plus, Fourth Edition

Data: Data-Type Keywords

Beyond the distinction between variable and constant is the distinction between different types of data. Some data are numbers. Some are letters or, more generally, characters. The computer needs a way to identify and use these different kinds. C does this by recognizing several fundamental data types. If a datum is a constant, the compiler can usually tell its type just by the way it looks: 42 is an integer, and 42.100 is floating point. A variable, however, needs to have its type announced in a declaration statement. You'll learn the details of declaring variables as you move along. First, though, take a look at the fundamental types recognized by C. K&R C recognized seven keywords relating to types. The C90 standard ...