Function Definition

FUNCTION DEFINITION

When a function is defined, space is allocated for that function in the memory. A function definition comprises two parts:

• Function header

• Function body

Programming Tip: It is an error to place a semicolon after the function header in the function definition.

The syntax of a function definition can be given as:

 return_data_type function_name (data_type variable1, data_type variable2, ...)

{

………...

statements

…….......

return (variable);

}

The number of arguments and the order of arguments in the function header must be same as that given in the function declaration statement.

Programming Tip: The parameter list in the function definition as well as function declaration must match.

While return data_type_function_name (data_type variable1, data_type variable2,..) is known as the function header, the rest of the portion comprising of program statements within {} is the function body which contains the code to perform the specific task.

The function header is same as function declaration. The only difference between the two is that a function header is not followed by a semicolon. The list of variables in the function header is known as the formal parameter list. The parameter list may have zero or more parameters of any data type. The function body contains instructions to perform the desired computation in a function.

Programming Tip: A function can be defined either before or after main().

The function definition itself can act as an implicit function declaration. So the programmer may skip the function declaration statement in case the function is defined before being used.

Note

The argument names in the function declaration and function definition need not be the same. However, the data types of the arguments specified in function declaration must match with that given in function definition.