1. Introduction to Programming
Lecture 37

2. Operator Overloading

3. Stream Insertion / Extraction
Operator Overloading
Stream Insertion / Extraction

4. int i ;
cin >> i ;

5. int a , b , c ;
a + b + c ;

6. cin >> i >> j ;

7. Friend Function

8. Member Operators

9. Object.data Object.function ( )

10. Stream Insertion Operator

11. int i = 5 , j = 10 , k = 15 ;
cout << i << j << k ;

12. ostream & operator << ( ostream & output , vehicle A )
Return type:
Reference to the output stream
Operator } }
ostream & operator << ( ostream & output , vehicle A )
Reference to the output stream
Object of the class

13. Definition
ostream & operator << ( ostream & output , vehicle d ) {
output<< d.seats ;
output<<d.tires ;
return output ; }

14. cout << d ;

15. cout << “The description of the vehicle is \n” << d ;

16. Example class Matrix { private :
          int rows , cols ;           int elements [ 3 ] [ 3 ] ;
public :
Matrix ( int rows = 3 , int cols = 3 ) ;
  friend ostream & operator << ( ostream & output , Matrix m ) ;
} ;

17. Example ostream& operator << ( ostream & output , Matrix m ) {
for ( int i = 0 ; i < m.rows ; i ++ )     {         for ( int j = 0 ; j < m.cols ; j ++ )         {           output << m.elements [ i ] [ j ] ;         }     }     return output ; }

18. int i ;
cin >> i ;

19. Matrix x ;
cin >> x ;

20. Example class Matrix { private : int rows, cols ;
int elements [ 3 ] [ 3 ] ;
public :
Matrix ( int rows = 3 , int cols = 3 ) ;
friend ostream & operator << ( ostream & output , Matrix m ) ;
  friend istream & operator >> ( istream & input , Matrix m ) ; };

21. Example
istream & operator >> ( istream & input , Matrix & m ) { cout<< “Please enter the values of the matrix” ;
    for ( int i = 0 ; i < m.rows ; i ++ )     {         for ( int j = 0 ; j < m.cols ; j ++ )         {           cout << “Please enter the values of elements ” << i << “,” << j ;
input >> m.elements [ i ] [ j ] ;         }     }     return input; }

22. Example
Matrix m ;
m.getMatrix ( ) ;
m.displayMatrix ( ) ;

23. Example
Matrix m ;
cin >> m ;
cout << m ;