Chapter 16, Problem 16.5E

(Function Prototypes and Definitions) Explain the difference between a function prototype and a function definition.

Program Plan Intro

To explain the difference between function prototype and function definition.

Explanation of Solution

Explanation:

Function prototype	Function definition
It provides function declaration.	It provides body of the function.
Data types are mandatory, name of arguments passed are optional	Name of argument must be specified along with their data types.
Always terminates with semicolon.	Doesn’t contain a semicolon at the end
It informs the compiler that the function is present in the program.	It contains the code that defines the purpose of the function.
Example: void sum(int, int);	Example: Void sum ( int a, int b) { Statement. }

Function prototype:

• To declare a function, the prototype function is used.
• It does not include the function's core, only tells the compiler about the name and return type of the function.
• It states, if any, the list of the passed arguments along with their data types.
• The compiler utilizes prototype details to guarantee the appropriate function description and correctness of the data types of arguments.
• The name of the arguments is discretionary in a function prototype; however, description of its data types is mandatory.
• It always ends with a semicolon, unlike a function description that does not end with a semicolon.

Function definition:

• The function definition gives the genuine code that is executed by the compiler.
• In the function definition the intended purpose for which the function has been developed is defined.
• Therefore, unlike a function declaration, a function definition provides the function body together with a header which is the code that makes up the function.
• On the off chance that we have a function definition in the program without a function prototype then the compiler will produce an error message.
• The function header doesn't contain a semicolon in function definition.