The document discusses operator overloading in C++. It provides examples of overloading unary operators like prefix and postfix increment (++), overloading binary operators like addition (+), and discusses issues like pre-increment vs post-increment, returning references vs objects from overloaded functions, and making operator functions friends of the class. Key concepts covered include overloading operators as class member or non-member functions, returning the object by reference or value, and handling operator precedence.

1. Prepared by
Mohammed Sikander
Technical Lead
Cranes Software
Mohammed.sikander@cranessoftware.com
Operator Overloading

2. 1. *
2. ->
3. .
4. ( )
5. &&
Mohammed Sikander cranesvarsity.com

3.  ++
 =
 [ ]
 <<
Mohammed Sikander cranesvarsity.com

4. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0)
{
feet = ft ; inch = in;
}
Distance operator ++( )
{
…..
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1(2 , 6);
2. ++d1;
3. d1++;
}
Is it post Increment / pre Increment

5. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0){
feet = ft ; inch = in;
}
Distance operator ++(int )
{
…..
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1(2 , 6);
2. ++d1;
3. d1++;
}
Is it post Increment / pre
Increment

6. class Distance{
private : int feet , inch;
public :
Distance(int ft = 0 , int in = 0)
{
feet = ft ; inch = in;
}
void operator ++( )
{
++feet;
}
void print( )
{
cout <<feet<<“’”<<inch<<“”” <<endl;
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1(2 , 6)
2. Distance d2;
3. ++d1;
4. d2 = ++d1;
5. d1.print( );
6. d2.print( );
}

7. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0)
{
feet = ft ; inch = in;
}
Distance operator ++( )
{
++feet;
return *this;
}
void print( )
{
cout <<feet<<“’”<<inch<<“”” <<endl;
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1(2 , 6)
2. Distance d2;
3. d2 = ++d1;
4. d1.print( );
5. d2.print( );
}

8. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0)
{
feet = ft ; inch = in;
}
Distance operator ++( int )
{
feet++;
return *this;
}
void print( )
{
cout <<feet<<“’”<<inch<<“”” <<endl;
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1(2 , 6) ,d2;
2. d2 = d1++;
3. d1.print( );
4. d2.print( );
}

9. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0)
{
feet = ft ; inch = in;
}
Distance operator ++(int )
{
Distance temp = *this;
feet++;
return temp;
}
void print( )
{
cout <<feet<<“’”<<inch<<“”” <<endl;
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1(2 , 6) ,d2;
2. d2 = d1++;
3. d1.print( );
4. d2.print( );
}

10. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0)
{
feet = ft ; inch = in;
}
Distance operator ++( )
{ cout <<“Pre Increment n”;
……
}
Distance operator ++(int )
{ cout <<“Post Increment n”;
……
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1(2 , 6) ,d2;
2. d2 = ++d1++;
}

11. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0)
{
feet = ft ; inch = in;
}
Distance operator ++( ){
cout <<“this = “ << this << endl;
feet++;
return *this;
}
void print( )
{
cout <<feet<<“’”<<inch<<“”” <<endl;
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1(2 , 6);
2. Distance d2;
3. cout <<&d1 << endl;
4. d2 = ++++d1;
5. d1.print( );
6. d2.print( );
}
Change the return type to
Distance & operator ++( )

12. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0){
feet = ft ; inch = in;
}
Distance operator +(const Distance &d)
{
………
}
};
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1 = 5;
2. Distance d2(2 , 6);
3. Distance d3;
4. d3 = d1 + 5;
5. d3 = 5 + d2;
}

13. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0)
{
feet = ft ; inch = in;
}
};
Distance operator +(const Distance &d1,const Distance &d2)
{
Distance temp;
return temp;
}
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1 = 5;
2. Distance d2(2 , 6);
3. Distance d3;
4. d3 = d1 + 5;
5. d3 = 5 + d2;
}

14. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0){
feet = ft ; inch = in;
}
};
Distance operator +(const Distance &d1,const Distance &d2)
{
Distance temp(d1.feet + d2.feet , d1.inch +d2.inch);
if(temp.inch >= 12)
{
temp.inch -= 12;
temp.feet++;
}
return temp;
}
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1 = 5;
2. Distance d2(2 , 6);
3. Distance d3;
4. d3 = d1 + 5;
5. d3 = 5 + d2;
}

15. class Distance{
private : int feet , inch;
public : Distance(int ft = 0 , int in = 0){
feet = ft ; inch = in;
}
friend Distance operator +(const Distance &d1,const Distance &d2);
};
Distance operator +(const Distance &d1,const Distance &d2)
{
Distance temp(d1.feet + d2.feet , d1.inch +d2.inch);
if(temp.inch >= 12)
{
temp.inch -= 12;
temp.feet++;
}
return temp;
}
Mohammed Sikander cranesvarsity.com
int main( )
{
1. Distance d1 = 5;
2. Distance d2(2 , 6);
3. Distance d3;
4. d3 = d1 + 5;
5. d3 = 5 + d2;
}