The function declaration

The common form of function declaration is

datatype        function-name          (datatype       argument1,    datatype aregument2 ...datatype argument );

In the given syntax, data type tells the function return data type. A Function name is user defined function name.  That can be given by using the rules for naming variable.  Within parentheses parameters or argument are declared with its data type. Any number of arguments can be as given.

Example:

void starline( );

the above declaration tells the compiler which at a few later point we plan to present a function known as starline. The key word void specifies in which the function has no return value, and the empty parentheses denotes that it takes no arguments.  The function declaration is terminated with semicolon.

Function declarations are also known as prototypes, because they give a model or blueprint for the function. That tells the compiler, "A function that looks like as this is coming up later in the program."