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Define Storage class

Types of Storage Class

Category of Functions

Type casting

Define Functions & category of Functions

Inline Function

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cin

cout

getc()putc()

A series of Instructionsthat are to be executed

more than once

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USER DEFINED FUNCTION :

SYNTAX :

retu_datatype func_name(arguments){

Body of the function

statements;return;

}

call the function from main() :

syntax :

func_name(arguments );

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#include

Void hai() // function prototype declaration

void hai() //definition

{

Cout

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NO ARGUMENT NO RETURN VALUES

ARGUMENT BUT NO RETURN VALUES

NO ARGUMENT WITH RETURN VALUES

WITH ARGUMENT WITH RETURN VALUES

(Based on Return values and passing Arguments)

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#include

#include

void main()

{

void message();

clrscr();cout

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/* To perform Addition of two numbers

Without Argument and With Return values */

#include

#include

int add(); //function prototype declarationvoid main()

{

int c;

c=add(); /* Return Variable - c */Cout

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#include#includevoid main(){int b,h;float a;

float area(int,int);clrscr();couth;a=area(b,h);cout

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Every C++ variable has a characteristic called its Storage Class.

All variables have datatype and storage classes

Keyword Where it is Declared

Storage Area Default Initial value Lifetime of a variable

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1. Local or Auto or Internal variable

2. External or Global variable

3. Static variable

4. Register Variable

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Auto variable are always declared

within a function and they are local

to the function in which they are

declared. Hence they are alsonamed as local variables

Keyword : auto

Declaration : Inside the functionStorage Area : Stack

Initial Value : Garbage value

(At the time of compilation

compiler assigns any value)

Lifetime : Upto that function only

Example :

auto int x; (or) int x;

#includevoid function1();void function2();void main()

{int m=1000;function2();cout

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#include#include

void main()

{

auto int x; //same as int x;clrscr();

cout

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A variable which can be accesswith in a function and outsidethemain function. These variables

are also named as Globalvariables or External variablesKeyword : extern

Declaration : Outside of the

main() functionStorage Area : CPUmemory

Initial Value : Garbage value

(At the time of compilation

compiler assigns any value)

Lifetime : Upto the entire

program

#includeint k;void function1();void function2();void function3();

void main(){k=20;function1();function2();function3();

}void function1() {k=k+10;cout

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#include#include

//To Access Data or Function Which is External to

that Function

int x=100;

void main()

{

int x=1000;

clrscr();

cout

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This variable static is constant andthe value is continued in all thesteps.

Keyword : static

Declaration : Inside the functionStorage Area : CPU memory

Initial Value : Zero

Lifetime : The value of the variable

persists between different functioncalls.

Example :

static int x;

/* To print the value of x */#includevoid stat();void main()

{int i;for(i=1;i

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#include#include

void main()

{

static int x;clrscr();

cout

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/* Example 2 */#include#includevoid incre(); /* Function prototype

declaration */void main(){clrscr();incre();

incre();incre();getch();}

void incre(){static char x=65;cout

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These variables are stored in CPU

registers and hence they can be

accessed faster than the one which is

stored in memory.

Keyword : register

Declaration : Inside the function

Storage Area : CPU - Register

Initial Value : Garbage value(At the time

of compilation compiler assigns anyvalue)

Lifetime : Upto that function only

Example : register int x;

Note :

register double x; register float y;

Registers are usually a 16bit therefore it

cannot hold a float or double data type value

which require 52 & 64 bytes respectively for

storing a value. But the compiler would treat

as automatic variables

#include#includevoid main(){

register int x;clrscr();Cout

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#include#include

void main()

{

register int i;clrscr();

cout

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#include

#includevoid main()

{

int a=10,b;

float c=2.3;

clrscr();b=int(a+c);

Cout

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This is used to convert one data type to another data type. The automatic typeconversions for evaluating an expression are given below -

For example,

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Inline function

Basically function are used to save the memory space.

When the compiler sees a function it jumps back to

instruction following to the call.It takes extra time to execute .

To avoid this slow down process inline function are

used.

Inline is a function that is expanded in line when it is

invoked. The compiler replaces the function call when it is

invoked

To make a function as inline ,the inline keyword must

be used before function definition

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An Inline function is a function with a few statements that is

expanded inline when it is invoked

An inline function specifier is actually a request and not a

command to the compiler, hence it may ignore the request and

compile the function as an ordinary function

Automatic inlining is the process of defining a function inside

the class declaration

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Common Restrictions while using Inline

An inline function must be defined before it is used.

It should not contain any loops

It should not be recursive

It should not contain any static variables

It should not contain a goto or a switch statement

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Example for inline function#include

inline float cmtom(int cm){

return (float)cm/100;

}

void main()

{

int cm;

clrscr();

cout

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// Demonstrate INLINE Functions

#include

float convert(float);

inline float convert(float pounds)

{

float c;

c=0.453592 * pounds;

return(c);

}void main()

{

float w,res;

cout

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An Inline function is a function with a few statements that is

expanded inline when it is invoked

An inline function specifier is actually a request and not a

command to the compiler, hence it may ignore the request and

compile the function as an ordinary function