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DESCRIPTION
Operator overloadingEnabling C++’s operators to work with class objectsUsing traditional operators with user-defined objectsRequires great care; when overloading is misused, program difficult to understandExamples of already overloaded operatorsOperator + and -, perform arithmetic on multiple typesCompiler generates the appropriate code based on the manner in which the operator is used
Citation preview
Deepali Singla
Assistant Professor
Chandigarh university
Polymorphism
1
Polymorphism
Polymorphism is the ability to use an operator or function in
different ways.
Polymorphism gives different meanings or functions to the operators
or function.
Poly, referring too many, signifies the many uses of those operators
and functions
A single function usage or an operator functioning in many ways can
be called polymorphism.
Polymorphism refers to codes, operations or objects that behave
differently in different contexts.
2
Types of Polymorphism
Two types of polymorphism:
Compile time
Function and operator overloading
Run time
Virtual Function
3
Compile time
This is also the early binding
In that compiler decide the scope of member function at the
compile time.
4
Function Overloading
Overloading a function Simply means, that a function is not
only defined its name but by its name and parameter types.
Function should be declare or define in same class
The following function are different :
int area(int I, int k);
void area(float I, float k);
float area();
5
Function Overloading
Overloading a function Simply means, that a function is not
only defined its name but by its name and parameter types.
Function should be declare or define in same class
The following function are different :
int area(int I, int k);
void area(float I, float k);
float area();
These three
methods are
different Bases on
there arguments
6
Function Overloading
class A
{
public:
void sum(int a, int b)
{
cout<<"Integers sum is :"<<(a+b)<<endl;
}
void sum(float a, float b)
{
cout<<"float sum = "<<(a+b)<<endl;
}
};
void main()
{
A a1;
float i=1.01,j=9.23;
a1.sum(2,5);
a1.sum(i,j);
}
Function overloading
7
Function Overloading
class A
{
public:
void sum(int a, int b)
{
cout<<"Integers sum is :"<<(a+b)<<endl;
}
void sum(float a, float b)
{
cout<<"float sum = "<<(a+b)<<endl;
}
};
void main()
{
A a1;
float i=1.01,j=9.23;
a1.sum(2,5);
a1.sum(i,j);
}
Output:
Integers sum is : 7
float sum = 10.24
8
Operator Overloading
When operator is overloaded with multiple jobs, it is known
as a operator overloading
Means one operator have different meaning.
It is a way to implement compile time polymorphism.
9
Operator Overloading
Rules :
Any symbol can be used as function name
If it is valid operator in c language
If it is preceded by operator keywords
You cannot overloaded sizeof and ?: (Conditional)
operator
10
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
};
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3=c1 + c2;
c3.showdata();
}
11
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
};
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3=c1 + c2;
c3.showdata();
}
Error
12
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
};
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
13
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
14
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a
b
functions
a
b
functions
a
b
functions
c1 c2 o1
a
b
functions
temp
a
b
functions
c3 15
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a
b
functions
a
b
functions
c1 c2 o1
a
b
functions
temp
a
b
functions
c3 16
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a= 6
b= 8
functions
a
b
functions
c1 c2 o1
a
b
functions
temp
a
b
functions
c3 17
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a= 6
b= 8
functions
a
b
functions
c1 c2 o1
a
b
functions
temp
a
b
functions
c3 18
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a= 6
b= 8
functions
a
b
functions
c1 c2 o1
a
b
functions
temp
a
b
functions
c3 19
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a= 6
b= 8
functions
a= 6
b= 8
functions
c1 c2 o1
a
b
functions
temp
a
b
functions
c3 20
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a= 6
b= 8
functions
a= 6
b= 8
functions
c1 c2 o1
a= 10
b
functions
temp
a
b
functions
c3 21
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a= 6
b= 8
functions
a= 6
b= 8
functions
c1 c2 o1
a= 10
b= 13
functions
temp
a
b
functions
c3 22
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a= 6
b= 8
functions
a
b
functions
c1 c2 o1
a= 10
b= 13
functions
temp
a
b
functions
c3 23
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
a= 4
b= 5
functions
a= 6
b= 8
functions
a
b
functions
c1 c2 o1
a= 10
b= 13
functions
temp
a = 10
b= 13
functions
c3 24
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
Output:
a= 10, b= 13
25
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
In place of add can we write
Sum ?
Yes
But can we write +
26
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex add(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1.add(c2);
c3.showdata();
}
In place of add can we write
Sum ?
Yes
But can we write +
Yes we can write + in place of
Function name using the
operator keyword 27
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex operator +(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1 + c2
c3.showdata();
}
Here we perform operator
overloading.
In that program + operator
used to add two complex no
But in normal case this is
used to add two primitive no.
28
Operator Overloading class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex operator +(complex o1)
{
complex temp;
temp.a= a + o1.a;
temp.b= b + o1.b;
return (temp);
} };
void main()
{
complex c1,c2,c3;
c1.setdata(4,5);
c2.setdata(6,8);
c3= c1 + c2
c3.showdata();
}
Output:
a= 10, b= 13
29
Unary operator overloading
Unary operator is a operator where we have only one
operant.
For example:
b=-a
Here – is a unary operator which is used to perform
negation operation
30
class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex operator -()
{
complex temp;
temp.a= -a;
temp.b= -b;
return (temp);
} };
void main()
{
complex c1,c2;
c1.setdata(4,5);
c2= -c1;
c2.showdata();
}
Unary operator overloading
31
class complex
{
private:
int a,b;
public:
void setdata(int x, int y)
{
a=x; b=y;
}
void showdata()
{
cout<<"a= "<<a<<", b= "<<b<<endl;
}
complex operator -()
{
complex temp;
temp.a= -a;
temp.b= -b;
return (temp);
} };
void main()
{
complex c1,c2;
c1.setdata(4,5);
c2= -c1;
c2.showdata();
}
Unary operator overloading
Output:
a= -4, b= -5
32
Run time
Run time polymorphism also called the dynamic binding or
late binding
Dynamic means object are created at run time
Dynamic binding offer a greater flexibility and higher level
of abstraction than static binding because it is done “on the
fly” when a program executes
33
Run time
Virtual function is the best example of run time
polymorphism
Virtual function :
if we define any function as a virtual that means that function cannot
bind at compile time.
Compiler perform late binding of that function
So using the virtual function we try to remove the ambiguity
problem in a program during the inheritance
34
Run time
class A
{
public:
void f1()
{
cout<< "hello"<<endl;
}
};
class B : public A
{
public:
void f1()
{
cout<<"hello there"<<endl;
}
};
void main()
{
A *p;
B ob;
p=&ob;
p->f1();
}
35
Run time
class A
{
public:
void f1()
{
cout<< "hello"<<endl;
}
};
class B : public A
{
public:
void f1()
{
cout<<"hello there"<<endl;
}
};
void main()
{
A *p;
B ob;
p=&ob;
p->f1();
}
Output:
hello
36
Run time
class A
{
public:
void f1()
{
cout<< "hello"<<endl;
}
};
class B : public A
{
public:
void f1()
{
cout<<"hello there"<<endl;
}
};
void main()
{
A *p;
B ob;
p=&ob;
p->f1();
}
Output:
hello
This is wrong because we want to execute drive
class’s function f1() but here execute base class’s function.
So that’s why we perform late binding . But how can be do
that?
Using the virtual keywords.
Syntax:
virtual <return type> <name of function> <no. of
arg.> 37
Run time
class A
{
public:
virtual void f1()
{
cout<< "hello"<<endl;
}
};
class B : public A
{
public:
void f1()
{
cout<<"hello there"<<endl;
}
};
void main()
{
A *p;
B ob;
p=&ob;
p->f1();
}
Output:
hello
Function define as a virtual
38
Run time
class A
{
public:
virtual void f1()
{
cout<< "hello"<<endl;
}
};
class B : public A
{
public:
void f1()
{
cout<<"hello there"<<endl;
}
};
void main()
{
A *p;
B ob;
p=&ob;
p->f1();
}
Output:
Hello there
Function define as a virtual
39
Run time
Static Binding Dynamic Binding
Static binding means that the
legality of a member function
invocation is checked at the
earliest possible moment : by
the compiler at compile time.
The compiler uses the static
type of the pointer to
determine weather the
member function invocation
is legal
Dynamic binding means that
the address of the code in a
member function invocation
is determined at the last
possible moment: based on
the dynamic type of the
object at run time. It is called
“dynamic binding” because
the binding to the code that
actually gets called as
accomplished dynamically (at
run time). 40
Run time
Static Binding Dynamic Binding
With static binding, you get
better run time efficiency
because the compiler can
actually optimize the code
before running it.
The CLR knows how much
memory to take up for the
static method object
Dynamic binding offers
greater flexibility and a higher
level of abstraction than static
binding because it is done “on
the fly” when a program
executes.
The CLR doesn't know how
much memory to take up for
the dynamic method object
41
ThanQ
42
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