Exercise 4.3

Consider the following global data:

string program_name; 


string version_stamp; 


int version_number; 


int tests_run; 


int tests_passed; 

Write a class to wrap around this data.

Why might we wish to do this? By wrapping these global objects within a class, we encapsulate their direct access within a small set of functions. Moreover, the names of the objects are now hidden behind the scope of the class and cannot clash with other global entities. Because we wish only a single instance of each global object, we declare each one to be a static class member as well as the member functions that access them.

#include <string> 


using std::string; 





class globalWrapper { 


public: 


    static int tests_passed()     { return _tests_passed; } 


    static int tests_run()        { return _tests_run; } 


    static int version_number()   { return _version_number; } 


    static string version_stamp() { return _version_stamp; } 


    static string program_name()  { return _program_name; } 





    static void tests_passed( int nval )  { _tests_passed = nval; } 


    static void tests_run( int nval )     { _tests_run = nval; } 





    static void version_number( int nval ) 


                { _version_number = nval; } 





    static void version_stamp( const string& nstamp ) 


                { _version_stamp = nstamp; } 





    static void program_name( const string& npn ) 


                { _program_name = npn; } 





private: 


   static string  _program_name; 


   static string  _version_stamp; 


   static int     _version_number; 


   static int     _tests_run; 


   static int     _tests_passed; 


}; 





string globalWrapper::_program_name; 


string globalWrapper::_version_stamp; 


int globalWrapper::_version_number; 


int globalWrapper::_tests_run; 


int globalWrapper::_tests_passed;