C++ Introduction

 

   C++

Introduction

C++ is a general purpose, case-sensitive, free-form programming language that supports object-oriented, procedural and generic programming.

C++ is a middle-level language, as it encapsulates both high and low level language features.

C++ history

C++ programming language was developed in 1980 by Bjarne Stroustrup at bell laboratories of AT&T (American Telephone & Telegraph), located in U.S.A.

Bjarne Stroustrup is known as the founder of C++ language.

C++ Features

1.     Simple

2.     Object-Oriented

3.     Reusability

4.     Memory Management

5.     Extensible

Usage of C++

By the help of C++ programming language, we can develop different types of secured and robust applications:

• Window application
• Client-Server application
• Device drivers
• Embedded firmware etc

s.no.	C	C++
1)	C follows the structure or procedural oriented language.	C++ object oriented language.
2)	Data is less secured in C.	In C++, Data is more secured.
3)	C follows the top-down approach.	C++ follows the bottom-up approach.
4)	C does not support function overloading.	C++ supports function overloading.
5)	In C, scanf() and printf() are mainly used for input/output.	C++ mainly uses stream cin and cout to perform input and output operations.
6)	Operator overloading is not possible in C.	Operator overloading is possible in C++.
7)	C programs are divided into procedures	C++ programs are divided into functions and classes.
8)	C does not support the inheritance.	C++ supports inheritance.
9)	#include<stdio.h> Std -standard i -input o-output input - scanf output- printf	#include<iostream.h> i-input o-output stream input - cin output - cout
10)	#include<conio.h> Console input output Getch clrscr	#include<conio.h> Console input output Getch clrscr
11)	main() { Program; }	Void main() { Program; }
12)	Sample program #include<stdio.h> #include<conio.h> main() { clrscr(); printf("hi hello\n"); printf("welcome to programtechie"); getch(); }	Sample program #include<iostream.h> #include<conio.h> void main() { clrscr(); cout<<"hi hello\n"; cout<<"welcome to programtechie"<<endl; getch(); }
13)	No OOPs concept	OOPS -object oriented programming structure Inheritance - generation Abstraction - data hiding Encapsulation - Data binding Polymorphism - Multi task Object - collections of data Class - collections of object

C++ Variable

value storage

datatype variable_name=value;   

int x=5,b=10;  //declaring 2 variable of integer type    

float f=30.8;    

char c='A';    

Rules for defining variables

A variable can have alphabets, digits and underscore.

A variable name can start with alphabet and underscore only. It can't start with digit.

No white space is allowed within variable name.

A variable name must not be any reserved word or keyword e.g. char, float etc.

Valid variable names:

int a;    

int _ab;    

int a30;    

Invalid variable names:

int 4;    

int x y;    

int double;

 

 

Runtime program

#include <iostream.h> 

#include <conio.h>

void main()  

{  

    int x, y;    // variable declaration.  

    clrscr();

    cout<<"Enter the values of x and y";  

    cin>>x>>y;  

    cout<<"Value of x"<<x<<endl;

    cout <<"Value of y is :"<<y; 

    getch();

} 

output

Enter the values of x and y

53

value of x=5

value of y=3

C++ Data Types

Types	Data Types
Basic Data Type	int, char, float, double, etc
Derived Data Type	array, pointer, etc
Enumeration Data Type	enum
User Defined Data Type	structure
Data Types	Memory Size	Range
char	1 byte	-128 to 127	%c
signed char	1 byte	-128 to 127
unsigned char	1 byte	0 to 127
short	2 byte	-32,768 to 32,767
signed short	2 byte	-32,768 to 32,767
unsigned short	2 byte	0 to 32,767
int	2 byte	-32,768 to 32,767	%d
signed int	2 byte	-32,768 to 32,767
unsigned int	2 byte	0 to 32,767
short int	2 byte	-32,768 to 32,767
signed short int	2 byte	-32,768 to 32,767
unsigned short int	2 byte	0 to 32,767
long int	4 byte		%ld
signed long int	4 byte
unsigned long int	4 byte
float	4 byte		%f
double	8 byte		%lf  or %ld
long double	10 byte

C++ Keywords

auto	break	case	char	const	continue	default	do
double	else	enum	extern	float	for	goto	if
int	long	register	return	short	signed	sizeof	static
struct	switch	typedef	union	unsigned	void	volatile	while