C FUNCTIONS

IN THIS POST WE SHALL DISCUSS ABOUT FUNCTIONS.

WHAT IS FUNCTION?

FUNCTION IS A TYPE OF BLOCK IN WHICH WE WRITE  SOME TASK  FOR PERFORM . WE CAN SAY , A FUNCTION IS A BLOCK OF CODE  THAT PERFORMS A SPECIFIC TASK .

SUPPOSE YOU WANT TO ADDITION AND SUBTRACTION OF TWO VALUES IN SAME PROGRAM . THEN , WHAT YOU DO ? YOU CAN CREATE TWO FUNCTIONS TO SOLVE THIS  PROBLEM .

i.) CREATE  AN ADDITION FUNCTION .
ii.) CREATE A SUBTRACTION FUNCTION .

IN THIS WAY , YOU CAN DIVIDE COMPLEX PROBLEMS INTO SMALL COMPONENT TO MAKE PROGRAM EASY TO UNDERSTAND AND USE .

*ADVANTAGES OF FUNCTION:-

i.) A SINGLE LONG PROGRAM GETS DIVIDED INTO SMALL PROGRAMMES  .

ii.) IF FUNCTION IS BEING USED THEN TO PERFORM THE SOME FUNCTION AGAIN  WITHIN THE PROGRAM , THE CODE NEED NOT BE WRITTEN AGAIN . ONLY ONE  LINE OF THE CALLING FUNCTION CAN BE WRITTEN .

iii.) SINCE FUNCTION WRITTEN IN ONE PROGRAM CAN BE USED IN ANOTHER   PROGRAM .


THERE IS TWO THINGS  IN USING OF FUNCTION :- FUNCTION DEFINITION AND FUNCTION DECLARATION .

FUNCTION DEFINITION IS DENOTED BY WITHOUT SEMI COLON LIKE

for example:-  ADD( )

FUNCTION DECLARATION IS DENOTED BY WITH SEMICOLON LIKE

for example:- ADD( ); 


TYPES OF FUNCTION :-
                                           THERE ARE TWO TYPES OF FUNCTION IN C PROGRAMMING .

• STANDARD LIBRARY FUNCTION 
• USER DEFINED FUNCTION 

1.) STANDARD LIBRARY FUNCTION:-
                                                                    STANDARD LIBRARY FUNCTION ARE BUILT IN FUNCTION IN C PROGRAMMING TO HANDLE TASK SUCH  AS MATHEMATICAL COMPUTATION , INPUT / OUTPUT PROCESSING , STRING HANDLING  ETC .

THESE FUNCTIONS ARE DEFINED IN HEADER  FILES .

for example:- printf( ) and scanf( ) function are define in "<stdio.h>" .

2.) USER DEFINED FUNCTION:-
                                                          C LANGUAGE ALLOWS PROGRAMMERS TO DEFINE FUNCTION , SUCH FUNCTION CREATED BY THE USER ARE CALLED USER DEFINED FUNCTION . A FUNCTION COMPRISES OF THE FOLLOWING ELEMENTS -

i.) FUNCTION DATA TYPE 
ii.) FUNCTION NAME 
iii.) ARGUMENT LIST
iv.) BODY OF THE FUNCTION

* THE FUNCTION DATA TYPE IS THE DATA TYPE OF THE VALUE , WHICH FUNCTION RETURN TO THE CALLING PROGRAM .

*  FUNCTION NAME IS THE ACTUAL NAME OF THE FUNCTION .

* ARGUMENT LIST IS A LIST OF VARIABLE ALONG WITH THERE DATA TYPE .

* BODY OF THE FUNCTION IS C LANGUAGE STATEMENT , WHICH ARE TO BE EXECUTED WITHIN THE FUNCTION .


TYPES OF USER DEFINED FUNCTION:-

i.) FUNCTION WITH NO ARGUMENT AND NO RETURN VALUE

ii.)  FUNCTION WITH ARGUMENT AND NO RETURN VALUE

iii.) FUNCTION WITH NO ARGUMENT AND   RETURN VALUE

iv.) FUNCTION WITH ARGUMENT AND RETURN VALUE   

ARGUMENT MEANS WHICH TYPE OF VARIABLE PASSED TO THE FUNCTION .

RETURN VALUE MEANS WHICH TYPE OF VALUE IS RETURNED FROM THE COMPILER . .
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NOTE:- CALL BY VALUE AND CALL BY REFERENCE WE SHALL DISCUSS IN OUR NEXT POST.
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FOR MORE KNOWLEDGE CLICK BELOW:-

basics-of-c-programing ( PREPROCESSOR)

basics-of-c-programming-2 (OPERATOR)

which-is-best-intel-or-amd.

diffrence-bw-structure-and-union.