// File: gradbook.cpp. Method definitions for GradeBook class

#include "gradbook.h"

//
// Constructor to obtain number of grades and possible points 
// for tests
// Pre:  none
// Post: NumGrades is the number of grades.
//       MaxTotalPoints is the number of possible points.
//

GradeBook::GradeBook()
{
   ReadNumGrades();
   GetMaxTotalPoints();
}

//
// Method to read number of grades
// Pre:  The GradeBook object has been created.
// Post: The (positive) number of grades was obtained.
//

void GradeBook::ReadNumGrades(void)
{
   cout << "How many grades are there? ";
   cin  >> NumGrades;
   while (NumGrades <= 0)
   {
      cout << "The number of grades must be positive.\n";
      cout << "How many grades are there? ";
      cin  >> NumGrades;
   }
}

//
// Method to obtain the maximum total number of points
// possible for a student to earn
// Pre:  The GradeBook object has been created.
// Post: The (positive) maximum possible points was obtained.
//

void GradeBook::GetMaxTotalPoints(void)
{
   cout << "\nEnter the value of each grade.\n";
   MaxTotalPoints = ReadAddGrades();
   while (MaxTotalPoints <= 0)
   {
      cout << "The grade total must be positive.\n";
      cout << "Please enter grades again.\n\n";
      MaxTotalPoints = ReadAddGrades();
   }
}

//
// Function to read and total grades and to return total
// Pre:  The GradeBook object has been created.
// Post: The nonnegative total grade points was returned.
//

int GradeBook::ReadAddGrades(void)
{
   int TotalPoints;  // total number of points

   TotalPoints = 0;
   for (int grade = 1; grade <= NumGrades; grade++)
      TotalPoints += ReadGrade(grade);

   return TotalPoints;
}

//
// Function to read and return an integer grade
// Pre:  grade is the number of the grade.
// Post: A nonnegative grade was returned.
//

int GradeBook::ReadGrade(int grade)
{
   int points;      // points for one test

   do
   {
      cout << "Enter the nonnegative value of grade " << grade << ": ";
      cin  >> points;
   }
   while (points < 0);

   return points;
}

//
// Function to compute and return the average of a student
// Pre:  NumGrades is the (positive) number of grades.
//       MaxTotalPoints is the (positive) total worth of grades.
//       student is the student number
// Post: A student's average was returned.
//

float GradeBook::GetAverage(int student)
{
   int TotalPoints;  // total number of points
   float average;    // student's average
   cout << "\nEnter the grades for student " << student << ".\n";
   TotalPoints = ReadAddGrades();
   average = 100.0 * TotalPoints / MaxTotalPoints;
   return average;
}