Introduction to c ++ part -1

Recall
• What are files handling used for?
• How do we write in to a file?
• What are the different modes of opening a
file?
• What is fgetc() ?

Introduction to C++
Week 4- day 1

C++
• Super Set of C
C++ was originally developed to be the next version of C, not a new
language.
• Backward compactable with C
Most of the C functions can run in C++
• Same compiler preprocessor
Must have a function names “main” to determine where the program starts

C Vs C++
• int
• Char
• Float
• double
“Exactly the same as
of left side”
Data Types

C Vs C++
• Conditional control
structures
– If
– If else
– Switch
• Loops
– for
– while
– Do while
of left side”
Control Structures

C Vs C++
int sum(int a, int b)
{
Int c;
c=a + b
return c;
}
sum(12,13)
of left side”
functions

C Vs C++
Int a[10];
Int b[] = {1000, 2, 3,
50}; “Exactly the same as
of left side”
Arrays

C Vs C++
Output
printf(“ value of a = %d”,a);
Printf(“a = %d and b= %d”,a,b);
Input
scanf(“%d ", &a);
Scanf(“%d”,&a,&b);
Output
cout<< “value of a =" << a;
Cout<<“a =”<<a<<“b=”<<b;
Input
cin>>a;
Cin>>a>>b;;
Input / Output

C Vs C++
char str[10];
str = "Hello!"; //ERROR
char str1[11] = "Call
home!";
char str2[] = "Send
money!";
char str3[] = {'O', 'K',
'0'};
strcat(str1, str2);
string str;
str = "Hello";
string str1("Call
home!");
string str2 = "Send
money!";
string str3("OK");
str = str1 + str2;
str = otherString;
Strings

C Vs C++
struct Data
{
int x;
};
struct Data module;
module.x = 5;
struct Data
{
int x;
void printMe()
{
cout<<x;
}
} Data;
Data module,Module2;
module.x = 5;
module2.x = 12;
module.printMe() // Prints 5
module.printMe() // Prints 12
Structures

• OOP concepts
• Operator overloading
What’s New in C++ ?

OOP Concept
• Object-oriented programming (OOP) is a
style of programming that focuses on
using objects to design and build
applications.
• Think of an object as a model of the
concepts, processes, or things in the real

Objects in real world
• Object will have an identity/name
 Eg: reynolds, Cello for pen. Nokia,apple for
mobile
• Object will have different properties which
describes them best
 Eg:Color,size,width
• Object can perform different actions
 Eg: writing,erasing etc for pen. Calling,

Objects
I have an identity:
I'm Volkswagen
I have different properties.
My color property is green
My no:of wheel property is 4
I can perform different actions
I can be drived
I can consume fuel
I can play Music
I have an identity:
I'm Suzuki
I have different properties.
My color property is silver
My no:of wheel property is 4
I can perform different actions
I can be drived
I can consume fuel
I can play Music

How these objects are created?
• All the objects in the real world are created
out of a basic prototype or a basic blue
print or a base design

Objects in the software world
• Same like in the real world we can create
objects in computer programming world
–Which will have a name as identity
–Properties to define its behaviour
–Actions what it can perform

How these objects are
created
• We need to create a base design which
defines the properties and functionalities
that the object should have.
• In programming terms we call this base
design as Class
• Simply by having a class we can create
any number of objects of that type

Definition
• Class : is the base design of
objects
• Object : is the instance of a class
• No memory is allocated when a class is
created.
• Memory is allocated only when an object is
created.

How to create class in
C++
class shape
{
Int width;
Int height;
Int calculateArea()
{
return x*y
}
}
public:

C++
class shape
{
Int width;
Int height;
Int calculateArea()
{
return x*y
}
}
Is the Keyword to create
any class
public:

C++
class shape
{
Int width;
Int height;
Int calculateArea()
{
return x*y
}
}
Is the name of the class
public:

C++
class shape
{
Int width;
Int height;
Int calculateArea()
{
return x*y
}
}
Called access specifier.
Will detailed soonpublic:

C++
class shape
{
Int width;
Int height;
Int calculateArea()
{
return x*y
}
}
Are two variable that
referred as the
properties
public:

C++
class shape
{
Int width;
Int height;
Int calculateArea()
{
return x*y
}
}
Is the only functionality
of this class
public:

How to create objects in
C++
shape rectangle,square;
rectangle.width=20;
recangle.height=35;
square.height=10;
square.width=10;
rArea=rectangle.calculateArea();
sArea=square.calculateArea();
Is the class name

C++
rectangle.width=20;
recangle.height=35;
square.height=10;
square.width=10;
Two objects of base type
shape

C++
rectangle.width=20;
recangle.height=35;
square.height=10;
square.width=10;
Setting properties of
object named rectangle

C++
rectangle.width=20;
recangle.height=35;
square.height=10;
square.width=10;
Setting properties of
object named square

C++
rectangle.width=20;
recangle.height=35;
square.height=10;
square.width=10;
Calling the functionality
of rectangle which is
claclulateArea();

Example
Class : shape
Height:35
width:20
Object rectangle
calculateArea()
{
Return 20*35
}
Height:10
width:10
Object square
calculateArea()
{
Return 10*10;
}
Member variables
Height
width
Member function
calculateArea
{
return height*width;
}

Access Specifier
• Access specifiers defines the access
rights for the statements or functions that
follows it until another access specifier or
till the end of a class.
• The three types of access specifiers are
–Private
–Public
–Protected

Access Specifier
class Base
{
public:
// public members go here
protected:
// protected members go here
private:
// private members go here
};

Class Vs Structure
• Class is similar to Structure.
• Structure members have public access by
default.
• Class members have private access by
default.

Self Check
• Which of the following term is used for a
function defined inside a class?
–Member Variable
–Member function
–Class function
–Classic function

Self Check
• cout is a/an __________ .
–Operator
–Function
–Object
–macro

Self Check
• Which of the following is correct about
class and structure?
– class can have member functions while
structure cannot.
– class data members are public by default
while that of structure are private.
– Pointer to structure or classes cannot be
declared.
– class data members are private by default
while that of structure are public by default.

Self Check
• Which of the following operator is
overloaded for object cout?
•>>
•<<
•+
•=

Self Check
• Which of the following access
specifier is used as a default in a
class definition?
•protected
•public
•private
•friend

Introduction to c ++ part -1

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