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C++ Operator Overloading

What is operator overloading
Rules for overloading Operators
Operator Overloading restrictions
List of operators that cannot be overloaded.
Overloading Unary operator
Overloading increment operator(++)
Overloading decrement operator(–)
Overloading unary operator(-)
Overloading increment operator(++) postfix
Overloading decrement operator(–) postfix
Overloading increment operator (++) with friend function
Overloading increment operator (–) with friend function
Increment the time using ++
Decrement the time using ++
Overloading Binary operator(+,-,*,/,%)
Add two object using “+” operator with friend function
Overloading “-” operator
Overloading “*” operator
Overloading “/” operator
Overloading “%” operator
overloading all (+,-,*,/,%)
Overloading “+” operator with friend function
class distance (feet,inches) with “+” operator
class distance (feet,inches) with “+” operator with friend function
class distance (km,m) with “+” operator
class distance (km,m) with “+” operator with friend function
class distance (m,cm) with “+” operator
class distance (m,cm) with “+” operator with friend function
class distance (km,m,cm) with “+” operator
class distance (km,m,cm) with “+” operator with friend function
class distance (km,m,cm,mm) with “+” operator
class distance (km,m,cm,mm) with “+” operator with friend function
class time(hh,mm,ss) with “+” operator
class time(hh,mm,ss) with “+” operator with friend function
class complex(real,ing) with “+” operator
class complex(real,ing) with “+” operator with friend function
class string(str) with “+” operator
class string(str) with “+” operator with friend function
overloading “+=” operator

C++:Overloading Unary operator

Overloading Unary operator
(++,–, -)

Example:1
Overloading increment operator (++)

// to overload ++ operator
#include<iostream>
#include<conio.h>
using namespace std;
class sample
{
private:
	int a;
public:
	sample();//defa
	sample(int n); //para
	void get();
	void disp();
	void operator++();
};
sample::sample()
{
	a=0;
}
sample::sample(int n)
{
	a=n;
}
void sample::get()
{
	cout<<"Enter the value of a ";
	cin>>a;
}
void sample::disp()
{
	cout<<"a= "<<a<<endl;
}
void sample::operator++()
{
	a=a+1;//a++;//++a;//a+=1;
}
int main()
{
  sample s1,s2;
  s1.get();
  s2.get();  //s1=10 s2=20
  s1.disp();
  s2.disp();
  ++s1; //s1.operator++();
  ++s1;
  ++s2;
  s1.disp();s2.disp();
  getch();
  return(0);
}

Output:

Enter the value of a 10
Enter the value of a 20
a= 10
a= 20
a= 12
a= 21

Example:2
Overloading decrement operator (–)

// to overload -- operator
#include<iostream>
#include<conio.h>
using namespace std;
class sample
{
private:
	int a;
public:
	sample();
	sample(int n);
	void get();
	void disp();
	void operator--();
};
sample::sample()
{
a=0;
}
sample::sample(int n)
{
a=n;
}
void sample::get()
{
cout<<"Enter the value of a ";
cin>>a;
}
void sample::disp()
{
cout<<"a= "<<a<<endl;
}
void sample::operator--()
{
  a=a-1;
}
int main()
{
	sample s1,s2;
	s1.get();s2.get();
	s1.disp();s2.disp();
	--s1; //s1.operator--();
	--s1;
	--s1;
	--s2;
	s1.disp(); s2.disp();
	getch();
	return(0);
}

Output:

Enter the value of a 10
Enter the value of a 20
a= 10
a= 20
a= 7
a= 19