CE142:OBJECT ORIENTED PROGRAMMING WITH C++
December 2018 – May 2019
UNIT 3
INTRODUCTION TO C++
Devang Patel Institute of Advance Technology and
Research
Objectives
• Learning the basics of C++ and its applications.
• Creating a simple C++ Program.
Unit – 3 : Introduction of C++
Introduction
In this chapter, we will discuss
•What is C++?
•Simple C++ Program
•Applications of C++
•Introduction to class, object and creating a simple C++
program
•Structure of C++ Program
Unit – 3 : Introduction of C++
C++
• C++ Developed in 1979
– Developed by Bjarne Stroustrup
– Developed at Bell Telephone laboratories
– Originally called “C with classes”
– The name C++ is based on C’s increment operator (++)
• Indicating that C++ is an enhanced version of C
Unit– 3 : Introduction of C++
Development of Program
Unit – 3 : Introduction of C++
Compiling
• The job of the compiler is:
– To check your program and make sure it follows the rules of the C+
+ language
• If it does not, the compiler will give you an error to help
pinpoint what needs fixing
– To convert each file of source code into a machine language file
called an object file
Unit – 3 : Introduction of C++
Linking
• Process of taking all the object files generated by the
compiler and combining them into a single executable
program that you can run
• This is done by a program called the linker
Unit – 3 : Introduction of C++
A Simple C++ program
The iostream file
#include <iostream> // include header file
using namespace std;
int main()
Comments
{
cout<<"C++ is better than C. \n"; Namespace (std
return 0; where standard class
libraries defined)
}
Output Operator
Unit – 3 : Introduction of C++
A C++ program
/* include headers; these are modules that include functions that you may use in
your program; we will almost always need to include the header that defines cin
and cout; the header is called iostream.h */
#include <iostream.h>
int main() {
//variable declaration
//read values input from user
//computation and print output to user
return 0;
}
After you write a C++ program you compile it; that is, you run a program called compiler
that checks whether the program follows the C++ syntax
– if it finds errors, it lists them
– If there are no errors, it translates the C++ program into a program in machine
language which you can execute
Unit – 3 : Introduction of C++
Contd..
• what follows after // on the same line is considered comment
• indentation is for the convenience of the reader; compiler ignores all spaces
and new line ; the delimiter for the compiler is the semicolon
• all statements ended by semicolon
• Lower vs. upper case matters!!
– Void is different than void
– Main is different that main
Unit – 3 : Introduction of C++
Hello world program
Here is the Hello world program in C++.
#include <iostream.h>
int main()
{
cout << “Hello world!”;
return 0;
}
Unit – 3 : Introduction of C++
Contd..
// my first program in C++
#include <iostream>
int main()
std::cout << "Hello World!";
Unit – 3 : Introduction of C++
Contd..
• #include <iostream>
Lines beginning with a hash sign (#) are directives read and interpreted by
what is known as the preprocessor. They are special lines interpreted before
the compilation of the program itself begins.
In this case, the directive #include <iostream>, instructs the preprocessor to
include a section of standard C++ code, known as header iostream, that allows
to perform standard input and output operations, such as writing the output of
this program (Hello World) to the screen.
Unit – 3 : Introduction of C++
Contd..
• std::cout << "Hello World!";
This line is a C++ statement.
A statement is an expression that can actually produce some effect.
Statements are executed in the same order that they appear within a
function's body.
Unit – 3 : Introduction of C++
Using namespace std
• If you have seen C++ code before, you may have seen cout being used
instead of std::cout.
• Both name the same object: the first one uses its unqualified name
(cout), while the second qualifies it directly within the namespace std
(as std::cout).
• cout is part of the standard library, and all the elements in the standard
C++ library are declared within what is called a namespace: the
namespace std.
Unit – 3 : Introduction of C++
Contd..
• In order to refer to the elements in the std namespace a program shall
either qualify each and every use of elements of the library (as we have
done by prefixing cout with std::), or introduce visibility of its
components. The most typical way to introduce visibility of these
components is by means of using declarations:
• using namespace std;
Unit – 3 : Introduction of C++
Example
// my second program in C++
#include <iostream>
using namespace std;
int main ()
cout << "Hello World! ";
cout << "I'm a C++ program";
Unit – 3 : Introduction of C++
more C++ statements
#include <iostream>
using namespace std; Variable
int main()
{
float number1, number2, sum, average;
cout << "enter two numbers: "; Input
cin >> number1; Operator
cin >> number2;
sum = number1 + number2;
average = sum/2;
cout << "sum =" << sum << "\n"; Cascading of
cout << "Average =" << average << "\n"; I/O Operators
return 0;
}
Unit – 3 : Introduction of C++
Comments
// This is a C++ program. It prints the sentence:
// Welcome to C++ Programming.
Or
/*
You can include comments that can
occupy several lines.
*/
Unit – 3 : Introduction of C++
Variable declaration
type variable-name;
Meaning: variable <variable-name> will be a variable of type <type>
Where type can be:
– int //integer
– double //real number
– char //character
Example:
int a, b, c;
double x;
int sum;
char my-character;
Unit – 3 : Introduction of C++
Input statements
cin >> variable-name;
Meaning: read the value of the variable called <variable-name> from
the user
The operator >> is known as the extraction or get from operator.
It extracts the value from the keyboard and assigns it to the
variable on the right.
Example:
cin >> a;
cin >> b >> c;
cin >> x;
cin >> my-character;
Unit – 3 : Introduction of C++
Input Operator
Unit – 3 : Introduction of C++
Output statements
cout << variable-name;
Meaning: print the value of variable <variable-name> to the user
cout << “any message”;
Meaning: print the message within quotes to the user
cout << endl;
Meaning: print a new line
The operator << is known as the insertion operator.
Multiple use of << in one statement is known as cascading.
Example:
cout << a;
cout << b << c;
cout << “This is my character: “ << my-character << “ he he he”
<< endl;
Unit- 3 : Introduction of C++
Output Operator
cout<< “c++ is better than c”;
cout<<name;
The operator << is called as insertion or put to operator
Unit – 3 : Introduction of C++
Cascading I/O Operators
The multiple use of << or >> in one statement is called
cascading.
Example:-
cout<< “ sum”<< sum << “\n”
First sends the string “sum=“ to cout and then sends the
value of sum.
Finally, it sends the newline character so that the next
output will be in the new line.
Example:-
cin>>number1>>number2;
Unit – 3 : Introduction of C++
Access Modifiers
Accessing a data member depends solely on the access
control of that data member.
This access control is given by Access modifiers in C++.
There are three access modifiers :
1. public
2. private
3. protected
Unit – 3 : Introduction of C++
Contd..
Public: A public member is accessible from anywhere outside the class
but within a program.
Private: A private member variable or function cannot be accessed, or
even viewed from outside the class. Private members can only be
accessed by member functions of the same class or friends. This
means derived classes can not access private members of the
base class directly!
Protected: A protected member variable or function is very similar to a
private member but it provided one additional benefit that they can be
accessed in child classes which are called derived classes.
Unit – 3 : Introduction of C++
Creating Simple program using class
#include<iostream>
using namespace std;
void show();
class Test
{
public:
void show()
{
cout << "I am a member function of class"<<"\n";
}
};
int main()
{
Test t;
t.show();
show();
}
void show()
{ cout << "I am a function defined outside the class"<<"\n";}
Unit – 3 : Introduction of C++
Common escape sequences
Escape Sequences Character
\a Bell (beep)
\b Backspace
\f Formfeed
\n Newline
\r Return
\t Tab
\\ Backslash
\’ Single quotation mark
\’’ Double quotation marks
\xadd Hexadecimal representation
Unit – 3 : Introduction of C++
Structure of C++ program
Include files
Class declarations
Member functions definitions
Main function program
Unit – 3 : Introduction of C++
The client-server model
Member function
Server
Class definition
Main function program Client
Unit – 3 : Introduction of C++
Real World Applications of C++
• Games
• Graphic User Interface (GUI) based applications
• Web Browsers
• Advance Computations and Graphics
• Database Software
• Operating Systems
• Enterprise Software
• Medical and Engineering Applications
• Compilers
35
Unit – 3 : Introduction of C++
Versions of C++
1. Apple C++
2. Borland C++
3. GNU C++ for Linux
4. IBM C++ for IBM power, System Z
5. SGI C++
6. Sun C++
7. Microsoft Visual C++ under .Net
8. Turbo C++
Unit – 3 : Introduction of C++
C++ versus C
The following features of C++ language or library is
not supported in C:
1.Classes
2.Constructors and destructors
3.Exceptions and try/catch block
4.Function overloading
5.Member functions
6.Namespaces
7.New and delete operators
8.Operator overloading
9.Standard template library (STL) [cmath, iostream,
cstdlib, cstring and many more]
Unit – 3 : Introduction of C++
Possible Future Additions to
C++
It is speculated that the following new features will be added to
C++ in future:
1.Automatic garbage collection
2.Object persistence
3.Support for concurrency and multithreading
4.Extensible member functions
5.Dynamically linked libraries
6.Rule based programming
Unit – 3 : Introduction of C++
Summary
• C++ supports interactive input and output features.
• A typical C++ program would contain 4 basic sections
namely file section, class declaration section, member
function section and main function section.
Unit – 3 : Introduction of C++
Exercise
1. WAP to display the following output using a single cout statement.
Maths=90
Physics=77
2. WAP that inputs a character from the keyboard and displays its
corresponding ASCII value on the screen
3. WAP to read two numbers from the keyboard and display the larger value
on the screen
4. WAP in C++ to print the sum of two numbers.
5. WAP in C++ to calculate the volume of a sphere.
Unit – 3 : Introduction of C++
Find errors, if any, in the following C+
+ statements
1. cout<<“x=“”x;
2. m=5;//n=10;//s=m+n;
3. cin>>x;>>y;
4. cout<<\n “Name:”<<name;
5. cout<<“Enter value:”; cin>>x;
6. /*Addition*/ z=x+y;
Unit – 3 : Introduction of C++
Fill in the blanks
1. The default access specifier for the class members
is_______.
2. ‘cin’ is an __________.
3. Runtime polymorphism is done using___________.
4. Which feature of the OOPS gives the concept of
reusability?
5. Mention the real time applications of C++.
42
Unit – 3 : Introduction of C++
Review questions
1. How does a main() function in C++ differ from main() in C?
2. Describe the major parts of a C++ program.
3. Why do we need the preprocessor directive #include
<iostream>?
4. List commonly used old-style header files along with the
contents and purpose and new version of the same.
5. List new header files included in ANSI C++
6. Applications of C++
Unit – 3 : Introduction of C++
Multiple Choice Questions
1. An expression A.B in C++ means ____
a. A is member of object B b. B is member of object A
c. Product of A and B d.None of these
2. A C++ code line ends with ___
a. A Comma (,) b. A Fullstop(.)
c. A Semicolon (;) d. A Slash (/)
2. Identify the C++ compiler of Linux
a.cpp b.g++
c.Borland d.vc++
• The default access specifier for the class members is
a.Public b.Private
c.Protected d.None of these
Unit – 3 : Introduction of C++
MCQ Answer
1. B
2. C
3. B
4. B
Unit – 3 : Introduction of C++
Presentation Prepared By:
Contact us:
dweepnagarg.ce@charusat.ac.in
parthgoel.ce@charusat.ac.in
hardikjayswal.it@charusat.ac.in
krishnapatel.ce@charusat.ac.in
khushipatel.ce@charusat.ac.in
michelemistry.ce@charusat.ac.in
Ms. Michele Mistry Ms. Krishna Patel Ms. Dweepna Garg
Subject Coordinator
Subject Teachers:
Mr. Parth Goel Mr. Hardik Jayswal Ms. Khushi Patel
https://parthgoelblog.wordpress.com
Devang Patel Institute of Advance Technology and Research
Thank You
47
Unit – 3 : Introduction of C++
