/*
 **************************************************************************
 * Program name : 010_Arithmetic_operations (Version 1.00)                *
 * Author       : Duck Wong                                               *
 * Language     : C / C++                                                 *
 * Compiler     : Boodshed Dec-C++ compiler Ver 3.95                      *
 * Computer     : PII350                                                  *
 * O/S          : Windows 98                                              *
 **************************************************************************
 * Version 1.00 : 2000/06/06 - first version                              *
 **************************************************************************
 * Description  : (a) input 2 numbers                                     *
 *                (b) select operator                                     *
 *                (c) calculation                                         *
 *                (d) output results                                      *
 **************************************************************************
*/
#include <iostream.h>
#include <stdlib.h>

int main()
{
      // part 1 : declaration
      char  selection;
      float Num_1, Num_2, Result;

      // part 2 : input numbers and operator
      cout << "\nPlease enter the first number : ";
      cin  >> Num_1;
      cout << "\nPlease enter the second number : ";
      cin  >> Num_2;
      do {
          cout << "\nOperators :  1= Addition       2= Subtraction"
               << "\n             3= Multiplication 4=Division"
               << "\n\nYour selection is : ";
          cin  >> selection;

          // part 3 : calculation
          switch (selection)                           // Note (1)
            {
             case '1' : Result=Num_1+Num_2; break;     // Note (2)
             case '2' : Result=Num_1-Num_2; break;
             case '3' : Result=Num_1*Num_2; break;
             case '4' : Result=Num_1/Num_2; break;
             default  : cout << "\n\aIncorrect selection !"; break;
            }
         } while (selection<'1' || selection>'4');

      // part 4 : output

      cout << "\n\nThe result of operation is : " << Result << "\n";

      system("PAUSE");
      return 0;
}

/* Notes
   (1) Switch structure :
       when using the switch structure (like the CASE structure in PASCAL),
       remember that it can only be used for testing a constant integral
       expression such data type char or int etc.
   (2) Break statement :
       The Break statement, when executed in a while, for, do/while, or
       switch structure, causes immediate exit from that structure. Common
       uses of the Break statement are to escape early from a loop, or to
       skip the remainder of a switch structure.
*/