1. Introduction to Programming
Lecture 33

2. In Today’s Lecture Operator overloading Assignment operator
A “this” pointer
Operator over loading using this pointer
Conversion function

3. Assignment Operator

4. a = b ;

5. Member Wise Assignment

6. Member Wise Copy

7. Example class String { char buf [ 100 ] ; public: String ( ) ;
...
} ;

8. Example main ( ) { String s1 ( “This is a test” ) ; String s2 ;
s2 = s1 ; … }

9. s2 = s1 ;

10. Example void String :: operator = ( String & s1 ) { delete buf ;
buf = new char [ s1.buf + 1 ] ;
strcpy ( buf , s1.buf ) ; }

11. Assignment Operator int i , j , k ; i = 5 ; j = 10 ; k = 15 ; i = j ;

12. i = j = k ; k = i = j ;

13. k = i = ++ j ;

14. this pointer

15. this pointer
buf ;
this -> buf ;
( * this ).buf ;

16. int i ;
i = i ; // nothing happens

17. String s [ 1000 ] = { “This is a Test” } ;
s = s ;

18. Self Assignment

19. Example
main ( ) {
String s , * sPtr ;
sPtr = & s ; .
s = * sPtr ; }

20. Example void String :: operator= ( String & other ) {
if ( this == & other )
return ; }

21. Example String & String :: operator = ( String & other ) {
if ( this == & other )
return * this ;
delete buf ;
buf = new char [ other.length + 1 ] ;
strcpy ( buf , other.buf ) ; }

22. s3 = s2 = s1 ;

23. cout << a << b << c ;

24. Example
Date d1 , d2 ;
d2 = d1 ++ ;
d2 = d1 + 1 ;

25. Example
Date date1 , date2 ;
date2 = date1 + 1 ;
date2 = date1 ++ ;

26. Example
main ( ) {
int i ;
float x ;
x = i ;
i = x ; }

27. Example
main ( ) {
Date d ;
int i ;
d = i ; } ?

28. Example
main ( ) {
int i ;
float x ;
x = ( float ) i ; }

29. Conversion Function

30. Date ( ) {
// body of function }

31. double x = 1 / 3 ; Output:
x * 3 ; Output:

32. Common Business Oriented Language