1. C++ <Template> 03/11/2009 1 Hadziq Fabroyir - Informatics ITS

2. How to implement ↓ in OOP ?¿ several methods withsame function statementsbut take different type of parameters 03/11/2009 Hadziq Fabroyir - Informatics ITS 2

3. What are you going to code ?¿ - to express swap function for various data type - 03/11/2009 Hadziq Fabroyir - Informatics ITS 3

4. Declare it one by one ?¿ void swapInt (int *a, int *b); void swapFloat (float *c, float *d); void swapChar (char *p, char *q); … // every methods has a specific name 03/11/2009 Hadziq Fabroyir - Informatics ITS 4

5. Make it more general , guys ! 03/11/2009 Hadziq Fabroyir - Informatics ITS 5

6. Function Overloading void swap (int *a, int *b) { int temp; temp = *a; *a = *b; *b = temp; } void swap (float *c, float *d) {float temp; temp = *c; *c = *d; *d = temp;} void swap (char *p, char *q) {char temp; temp = *p; *p = *q; *q = temp;} 03/11/2009 Hadziq Fabroyir - Informatics ITS 6

7. Here it is , C++ introduce <template> ! 03/11/2009 Hadziq Fabroyir - Informatics ITS 7

8. Why <templates> C++ promotes code reusability Inheritance and composition provide a way to re-use object code Templates provide a way to re-use source code Example: Queue<T> generic Queue having a type parameter T T can be replaced with actual types 03/11/2009 Hadziq Fabroyir - Informatics ITS 8

9. Why use <templates> Templates are easier to write. You create only one generic version of your class or function instead of manually creating specializations. Templates can be easier to understand, since they can provide a straightforward way of abstracting type information. Templates are type-safe. Because the types that templates act upon are known at compile time, the compiler can perform type checking before errors occur. 03/11/2009 Hadziq Fabroyir - Informatics ITS 9

10. <template> 03/11/2009 Hadziq Fabroyir - Informatics ITS 10

11. Function Template 03/11/2009 Hadziq Fabroyir - Informatics ITS 11

12. What’s it all about Easily create a large range of related functions or classes Function template - the blueprintof the related functions Template function - a specific function made from a function template 03/11/2009 Hadziq Fabroyir - Informatics ITS 12

13. Look at this declaration of Function Template template <class tipe> void swap(tipe &a,tipe &b) { tipe c; c = a; a = b; b = c; } 03/11/2009 Hadziq Fabroyir - Informatics ITS 13

14. Function Usage Example Instance of int void main(void) { int a,b; a = 10; b = 20; swap(a,b); cout << a << “ “ << b << endl; } Instance of float void main(void) { float a,b; a = 10.0; b = 20.0; swap(a,b); cout << a << “ “ << b << endl; } 03/11/2009 Hadziq Fabroyir - Informatics ITS 14

15. <template> effects It’s reusable ► we can gain the time for coding It’s possible to swap 2 objects instantiated from a class 03/11/2009 Hadziq Fabroyir - Informatics ITS 15

16. Overloading Template Function #include <iostream.h> template <class Tipe> void swap(Tipe &a,Tipe &b) { Tipe tmp; tmp = a; a = b; b = tmp; } 03/11/2009 Hadziq Fabroyir - Informatics ITS 16 void swap(float &a,float &b) { float c; a = (a < 0.00)?–a:a; b = (b < 0.00)?–b:b; c = a; a = b; b = c; }

17. Class Template 03/11/2009 Hadziq Fabroyir - Informatics ITS 17

18. Class Template template <class MyTipe> class CMyTemplate { protected : MyTipe m_a,m_b; public : void Done(void) { memset(&m_a,0,sizeof(MyTipe)); } }; 03/11/2009 Hadziq Fabroyir - Informatics ITS 18 /* method is declared outside the class*/ template <class MyTipe> void CMyTemplate<MyTipe>::Init(MyTipe a,MyTipe b) { m_a = a; m_b = b; }

19. Class Template on … struct template <class MyTipe> struct tMyStruct { MyTipe a,b; }; union template <class MyTipe> union _MyUnion { MyTipe a; int b; }; 03/11/2009 Hadziq Fabroyir - Informatics ITS 19

20. Class Template Usage void main(void) { CMyTemplate<short> a; tMystruct<short> b; _MyUnion<float> c; } 03/11/2009 Hadziq Fabroyir - Informatics ITS 20

21. Using 2 Type (Example) template <class MyTipe1,class MyTipe2> class CMyTemplate { protected : MyTipe1 m_a MyTipe2 m_b; public : void Init(MyTipe1 a,MyTipe2 b) { m_a = a; m_b = b; } }; 03/11/2009 Hadziq Fabroyir - Informatics ITS 21 void main(void) { CMyTemplate<short,float> a; }

22. For your practice … Exercise Declare and Define template for your latest Classes of ... Shape (ex: public getColor(), protected color) 2D Shape, 3D Shape (ex: public getArea(), protected edgeLength) Triangle, Circle, Square; Cube, Cylinder, Sphere Lab Session (Senin, 19.00 – 21.00) Please provide: the softcopy(send it by email – deadline Sunday 23:59) the hardcopy(bring it when attending the lab session) 03/11/2009 Hadziq Fabroyir - Informatics ITS 22

23. ☺~ Next: Exception HIndling ~☺ [ 23 ] Hadziq Fabroyir - Informatics ITS 03/11/2009