CBSE Class XI Computer Science Functions Class … · Advantages of using Functions Easier to...
Transcript of 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
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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.
S. Kiran PGT(Comp. Science), KV, Malleswaram
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Advantages of using Functions
Easier to maintain, update and debug. Enhances readability of the program
Reusability of code
S. Kiran PGT(Comp. Science), KV, Malleswaram
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TYPES OF FUNCTIONS
BUILT – IN FUNCTIONS USER DEFINED FUNCTIONS
S. Kiran PGT(Comp. Science), KV, Malleswaram
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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.
S. Kiran PGT(Comp. Science), KV, Malleswaram
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USER DEFINED FUNCTIONS
Are functions defined by the programmer.
That is YOU.
S. Kiran PGT(Comp. Science), KV, Malleswaram
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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
S. Kiran PGT(Comp. Science), KV, Malleswaram
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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
S. Kiran PGT(Comp. Science), KV, Malleswaram
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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(); }
S. Kiran PGT(Comp. Science), KV, Malleswaram
prototype
Func. call
Function definition
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S. Kiran PGT(Comp. Science), KV, Malleswaram
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S. Kiran PGT(Comp. Science), KV, Malleswaram
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S. Kiran PGT(Comp. Science), KV, Malleswaram
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S. Kiran PGT(Comp. Science), KV, Malleswaram
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S. Kiran PGT(Comp. Science), KV, Malleswaram
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Note: A function prototype is not required if the function definition appears before its calling function Program
S. Kiran PGT(Comp. Science), KV, Malleswaram
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RECAPITULATION
S. Kiran PGT(Comp. Science), KV, Malleswaram
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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?
S. Kiran PGT(Comp. Science), KV, Malleswaram
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