1. Introduction to Programming
Lecture 38

2. Today’s Lecture
User Define Manipulator
Static key word

3. User Define Manipulators

4. Example
int i = 10 ;
cout << setwidth ( 7 ) << i <<endl ;

5. Parameter Less Manipulators

6. cout << manipulator << otherdata ;

7. ostream & manipulatorName ( ostream & os ) ;

8. Definition ostream & manipulatorName ( ostream & os ) {
return os << userDefinedManipulator ; }

9. User Defined Manipulators
A Short Example
// Tab
ostream & tab ( ostream & output ) {
return output << '\t' ; }
// bell
ostream & bell ( ostream & output )
return output << '\a' ;
// Takes the cursr to next line
ostream & endLine ( ostream & output )
return output << '\n' << flush ;
void main ( )
cout << "Virtual " << tab << "University" << bell << endLine ; // Use of Mainpulator

10. Static

11. Static Are variables which exist for a certain amount of time which is
longer than an ordinary automatic
variable.

12. Global

13. Example int i ; void myfunction ( void ) {
for ( i = 0 ; i < 10 ; i ++ )
cout << i << endl ; }

14. Automatic Variable

15. State

16. static int i ;

17. static int i = 0 ; //Initialization
i = 0 ; //Ordinary Assignment Statement

18. Example void f ( void ) { static int i = 0 ; i ++ ;
cout << “Inside function f value of i : ” << i << endl ; }
main ( )
int j ;
for ( j = 0 ; j < 10 ; j ++ ) ;
f ( ) ;

19. Example class Truck { char a ; public : Truck ( char c ) a = c ;
cout << "Inside constructor for object " << a << endl ; }
~ Truck ( )
cout << "Inside destructor for object " << a << endl ;
} ;

20. Example Truck a ( 'A' ) ; main ( ) { Truck b ( 'B' ) ; f ( ) ; g ( ) ;
cout << “Function g has been called " << endl ; }

21. Example void f ( ) { Truck c ( 'C' ) ; } void g ( )
static Truck g ( 'G' ) ;

22. Example Output Inside constructor for object A
Inside constructor for object B
Inside constructor for object C
Inside destructor for object C
Inside constructor for object G
function g has been called
Inside destructor for object B
Inside destructor for object G
Inside destructor for object A

23. Static Data Member Inside A Class

24. File Scope

25. Example class Truck { public : int wheels ; int seats ; } ; main ( )
Truck A ;
A.seats ; }

26. Scope Resolution Operator::

27. Truck :: nameOfStaticDatamember = values ;

28. Example class SavingsAccount { } ; private : char name [ 30 ] ;
float accountNumber ;
float currentBalance ;
static float profitRate ; //
public :
SavingsAccount ( ) ;
//...
} ;

29. SavingsAccount :: profitRate = 3.0 ;

30. SavingsAccount A ;
A.profitRate ; // bad usage

31. A.profitRate = 4.0 ; // bad usage

32. SavingsAccount :: profitRate ;

33. Example class Student { public : static int howMany ;
Student ( ) { howMany ++ ; }
~ Student( ) { howMany -- ; }
void displayHowMany ( )
cout << "Number of students are " << howMany ; }
} ;
int Student :: howMany = 0 ;

34. Dynamic

35. What we covered today
Parameter Less Manipulation
Static Data