C++ How to Program, 10/e

... function’s name, its return type and the types of its parameters. This function prototype indicates that the function returns an int, has the name maximum and requires three int parameters to perform its task. Notice that the function prototype is the same as the first line of the corresponding function definition (line 20), but ends with a required semicolon.

Good Programming Practice 6.1

Parameter names in function prototypes are optional (they’re ignored by the compiler), but many programmers use these names for documentation purposes. We used parameter names in Fig. 6.3’s function prototype for demonstration purposes, but generally we do not use them ...