1. Introduction to Programming
Lecture 41

2. Templates

3. Types of Templates
Function Templates
Class Templates

4. Swap Function { int temp ; temp = i ; i = j ; j = temp ; }
void swap ( int & i , int & j ) {
int temp ;
temp = i ;
i = j ;
j = temp ; }

5. Function Overloading

6. Function Templates

7. template < class T >

8. return_type function_name ( argument_list )

9. Example int reverse ( int x ) { return ( - x ) ; }
double reverse ( double x )

10. Example template < class T > T reverse ( T x ) { return (- x ) ;}

11. Example
main ( ) {
int i ;
…….
reverse ( i ) ; }

12. Example main ( ) { int i ; … reverse ( i ) ; double y ;
reverse ( y ) ; }

13. Code Reuse

14. Example template < class T > void swap ( T & x , T & y ) {
T temp ;
temp = x ;
x = y ;
y = temp ; }

15. int a , b ;
char a , b ;
swap ( a , b ) ;

16. Example template < class T > void swap ( T & x , T & y ) {
T temp ;
temp = x ;
x = y ;
y = temp ; }

17. template < class T , class U >

18. Example template <class T> T larger ( T x, T y ) { T big ;
if ( x > y )
big = x ;
else
big = y ;
return ( big ) ; }

19. Example main ( ) { int i = 5 , j = 7 ; double x = 10.0 , y = 15.0 ;
cout << larger ( i , j ) << endl ;
cout << larger ( x , y ) << endl ;
// cout << larger ( i , y ) ; Error }

20. Example template <class T> void inverse ( T & x , T & y ) {
T temp ;
temp = x ;
x = y ;
y = temp ; }

21. Example template <class T> T inverse ( T x ) { return ( - x ) ;}

22. Example main ( ) { int i = 4 , j = 8 ; inverse ( i , j ) ;}

23. Example template <class T> T reverse ( T x ) { return ( - x ) ;}
void main ( )
double a = ;
reverse ( a ) ;
reverse <int> ( a ) ;

24. Example template <class T , class U> T reverse ( U x ) {
return ( - x ) ; }

25. Example main ( ) { double a = 8.8 ; reverse ( a ) ;
reverse <int> ( a ) ;
reverse <int , double> ( a ) ;
reverse<double , double> ( a ) ;
reverse<double , int> ( a ) ; }

26. Example class PhoneCall { private : int lengthOfCall ; char billCode ;
public :
PhoneCall ( const int i , char b ) ;
PhoneCall ( PoneCall & p ) ;
PhoneCall PhoneCall :: operator - ( void ) ;
void display ( void ) ;
} ;

27. Example template <class T> T reverse ( T x ) { return ( - x ) ;}

28. Example
PhoneCall reverse ( PhoneCall x ) {
return (- x ) ; }

29. Example PhoneCall PhoneCall :: operator - ( void ) {
PhoneCall temp ( * this ) ;
temp.billCode = 'C' ;
return ( temp ) ; }

30. Example main ( ) { PhoneCall a ( 10 , ‘S’ ) ; a.display ( ) ;
a = reverse ( a ) ; }