• Class
  • private versus public members
  • data members are usually kept private
  • access to the data members through the public member functions
  • How to write the member functions
  • first.cpp
• Inline functions
  • Implemented efficiently
  • one or two line code for the member functions can be just put in the class definition itself (animal1.cpp)
• Template
  • animal1.cpp has a class that works only for dogs
  • if we wanted similar class for cats, we will have to copy all the code for chaos_animal and replace dog with cat
  • Repetition
  • Repetition can lead to erroneous code
  • Use a template for chaos_animal
• General format of templates is

template <parameter-list>

class-definition or function-definition

• Parameter list can consist of one or more parameters sparated by a comma. The parameters can be any one of the basic types such as int, char, double, etc. A special type of parameter is called class. A parameter of the type class is used to specify the data types in C++.

template <class animal_type, int max_animals>

class chaos_animal

{

animal_type animal[max_animals];

public:

void cacophony();

};

• The class definition can use any one of the parameters defined in the parameters. The above example, uses animal_type and max_animals in the class definition
• The function definition is any valid function that uses any one of the parameters defined in the parameters.

template <class animal_type, int max_animals>

void chaos_animal<animal_type,max_animals>::cacophony()

{

• Assignment 1 (timer.cpp)

#include <time.h>

template <class algorithm_type>

class timer

{

public:

time_t timed(int n, algorithm_type t);

};

template <class algorithm_type>

time_t timer<algorithm_type>::timed(int n, algorithm_type t)

{

}

class dummy

{

public:

void work(int n){}

};

void main()

{

timer<dummy> test;

}

• Here we have two templates. Both templates take one parameter called algorithm_type which will be a valid class definition in C++.
• First template is for a class called timer. The class timer has a function member called timed which takes two parameters: one of type int and the other of type algorithm_type (from the parameter list of template) and returns a value to the type time_t (predefined in BC++).
• The second template is for a function called timed which takes two parameters: one of type int and the other of type algorithm_type and returns a value to the type time_t (predefined in BC++). This function happens to be a member function of timer<algorithm_type>.