Declaring a function - function prototypes
type functionName( type [argname] [, type, ...] );Example:
// declare a function prototype for the add function, taking two integer // arguments and returning their sum int add (int lhs, int rhs);
In C and C++, functions must be declared before the are used. You can declare a function by providing its return value, name, and the types for its arguments. The names of the arguments are optional.
A function definition counts as a function declaration.