CBSE Class XI Computer Science Functions Class … · Advantages of using Functions Easier to...

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What is a function?

Functions are nothing but sub-programs of a program .

Is a part of a program which performs a

particular task as desired by the programmer. It can be called anywhere in the program.

S. Kiran PGT(Comp. Science), KV, Malleswaram



Functions exhibit the feature of MODULARITY

in OOP (Object Oriented programming). What is Modularity? The act of breaking up larger programs into

smaller unit is called modularity.




Advantages of using Functions

Easier to maintain, update and debug. Enhances readability of the program

Reusability of code




TYPES OF FUNCTIONS

BUILT – IN FUNCTIONS USER DEFINED FUNCTIONS




BUILT – IN FUNCTIONS These are part of the compiler package, which are

defined in the standard library files also called header files.

For e.g.., string.h header file contains definition for the

following functions. strlen(), strcmp(), strrev () etc.




USER DEFINED FUNCTIONS

Are functions defined by the programmer.

That is YOU.




FUNCTION DEFINITION A function must be defined before it is used

anywhere in the program.

Three important things that must be remembered

1. Function prototype 2. Function call 3. Function Definition




FUNCTION PROTOTYPE

It has the following parts 1. Return type 2. Function Name 3. Parameters or Argument list For e.g.: int sum ( int x, int y) ;

Return type Name

Argument List

Function prototype must end with a semi

colon




FUNCTION DEFINITION AND CALL #include<iostream. h> int square ( int n) #include<conio.h> { void main() return n x n; { } clrscr(); int square(int); int a, s; cout<<“Enter value for a”; cin>>a; s = square(a); cout<<“Square of given no. is”<<s;

getch(); }


prototype

Func. call

Function definition



Note: A function prototype is not required if the function definition appears before its calling function Program




RECAPITULATION




Which feature of OOP does function exhibit? List the advantages of using functions?

Name the different types of functions. Three things to remember in a function ______ What does function prototype tell the compiler? What is meant by return type?




CBSE Class XI Computer Science Functions Class … · Advantages of using Functions Easier to...

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