/*
 **************************************************************************
 * Program name : 011_Grade_and_marks (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 upto 10 the test result                       *
 *                (b) count the no. of result to each grade               *
 *                (c) output results                                      *
 **************************************************************************
*/
#include <iostream.h>
#include <stdlib.h>

int main()
{
      // part 1 : declaration and set the initial values
      int index, marks, count_A, count_B, count_C, count_D, count_E, count_U;
      marks= count_A= count_B= count_C= count_D= count_E= count_U=0;

      // part 2 : input
      for (index=1; index<=10; index++)                     // Note (1)
        {
         do {
             cout << "Enter the test result (-1 means to stop) for student "
                  << index << " : ";
             cin  >> marks;
            } while (marks<-1 || marks>100);                // Note (2)
         if (marks==-1) break;                              // Note (3)
         if (marks>=90) count_A+=1;                         // Note (4)
         else if (marks>=80) count_B+=1;
         else if (marks>=70) count_C+=1;
         else if (marks>=60) count_D+=1;
         else if (marks>=50) count_E+=1;
         else count_U+=1;
        }

      // part 3 : output
      cout << "\n\aSummary of " << index-1 << " test results : ";   // Note (5)
      cout << "\nGarde A is " << count_A;
      cout << "\nGarde B is " << count_B;
      cout << "\nGarde C is " << count_C;
      cout << "\nGarde D is " << count_D;
      cout << "\nGarde E is " << count_E;
      cout << "\nGarde F is " << count_U << "\n" << endl;

      system("PAUSE");
      return 0;
}

/* Notes
   (1) for structure : for (index=1; index<=10; index++)
       index= 1  -- establish initial value of index to 1
       index<=10 -- test if the final value of index has not been reached
       index++   -- increment the value of index by 1

       Examples A: for (i=7; i<= 63; i+= 7)
                   means vary the variable i from 7 to 63 in steps of 7
       Examples B: for (i=10; i<= 0; i-= 2)
                   means vary the variable i from 10 downto 0 in steps of -2

   (2) while structure : while (marks<-1 || marks>100);
       Repeat the loop of asking the test results if the marks is out of
       range ( -1 to 100).

   (3) Specical flag : if (marks==-1) break;
       The for loop will be terminated when the valus of the variable index
       is greater than 10 (as explained in Note (1)) or the inpuuted marks
       is -1. The break statement causes immediate exit from the for
       structure at once.

   (4) assignment operator : count_A+=1;
                                             OLD count_A  NEW count_A
       count_A+=1; means count_A= count_A+1      6          6+1 = 7
       count_A+=5; means count_A= count_A+5      6          6+5 = 11
       count_A-=1; means count_A= count_A-1      6          6-1 = 5
       count_A*=2; means count_A= count_A*2      6          6*2 = 12
       count_A/=2; means count_A= count_A/2      6          6/2 = 3
       count_A%=4; means count_A= count_A%4      6          6%4 = 2 (remainder)

   (5) The number of valid test results is : index-1.
*/