It refers to a subprogram that is meant to do a certain task. It is basically used to execute a set of operations and return information to the main or calling function.
return_data_type function_name(data_type par1, data_type par2,...)
Function Declarations and Function Definitions
Every function in program must have a function declaration and a function definition. Function declaration refers to the functions name, return data type and parameters (function prototype) while Function definition refers to the implementation of a particular function. Function declaration and function definition appear together to form a function
Static type checking
It refers to the checking of the data types used in all functions are appropriate to the actual function
requirements. This ensures that any function cannot be called with wrong number of parameters or
inappropriate argument types i.e. C++ does not allow any function to be used before it has been declared and the reason is that the compiler can perform static type checking.
This is a function declaration statement that informs the compiler of the type of data returned by the
functions, the number of parameters the function expects and order in which they are expected.
return_type function_name (list of parameters);