//----------------------------------------------------------------------------
//
//   FILE           :   template_example.C
//   AUTHOR         :   Eugene Wallingford
//   CREATION DATE  :   February 11, 1997
//
//----------------------------------------------------------------------------
//
//   MODIFIED BY    :   Eugene Wallingford
//   DATE           :   September 23, 1997
//   DESCRIPTION    :   Changed program format somewhat for readability
//
//----------------------------------------------------------------------------

#include <assert.h>             // to be able to assert that new worked
#include <iostream.h>           // for standard streams

//----------------------------------------------------------------------------
//
//   CLASS          :   reader<CLASS>
//   DESCRIPTION    :   This template class provides simple prompted input
//                      with range data validation.
//
//----------------------------------------------------------------------------

template <class TYPE>
class reader
{
   public:

           reader(char* prompt);                  // Constructor
      TYPE read  (TYPE min, TYPE max);            // Access message

   private:

      char* my_prompt;                            // Member data object
};

//----------------------------------------------------------------------------

template <class TYPE>
reader<TYPE>::reader(char* prompt)
{
   my_prompt = new char [ strlen(prompt) + 1 ];   // Allocate memory
   assert( my_prompt != 0 );

   strcpy(my_prompt,prompt);                      // Copy the string
}

//----------------------------------------------------------------------------

template <class TYPE>
TYPE reader<TYPE>::read(TYPE min, TYPE max)
{
   TYPE value_to_read;

   cout << my_prompt << ".  "
        << "The value must be between "
        << min << " and " << max << ": ";
   cin  >> value_to_read;
   while ( (value_to_read < min) || (value_to_read > max) )
   {
      cout << endl << endl
           << "Sorry, but the value must be between "
           << min << " and " << max << "." << endl;

      cout << my_prompt << ": ";
      cin  >> value_to_read;
   }

   return value_to_read;
}

//----------------------------------------------------------------------------
//   A demonstration program that uses readers of two types.
//----------------------------------------------------------------------------

int main ()
{
   reader<int>  test1("Enter the temperature");

   int  temp1 = test1.read(0, 100);
   int  temp2 = test1.read(-100, -0);

   reader<char> test2("Enter your first initial");

   char temp3 = test2.read('a', 'z');
   char temp4 = test2.read('0', '9');

   cout << endl << endl << endl
        << "1. " << temp1 << endl
        << "2. " << temp2 << endl
        << "3. " << temp3 << endl
        << "4. " << temp4 << endl;
}

//----------------------------------------------------------------------------