1   // Fig. 7.22: GradeBook.h
 2   // Definition of class GradeBook that uses a
 3   // two-dimensional array to store test grades.
 4   // Member functions are defined in GradeBook.cpp
 5   #include <array>
 6   #include <string>
 7
 8   // GradeBook class definition
 9   class GradeBook
10   {
11   public:
12      // constants
13      static const size_t students = 10; // number of students
14      static const size_t tests = 3; // number of tests       
15
16      // constructor initializes course name and array of grades
17      GradeBook( const std::string &,
18         std::array< std::array< int, tests >, students > & );
19
20      void setCourseName( const std::string & ); // set the course name
21      std::string getCourseName() const; // retrieve the course name
22      void displayMessage() const; // display a welcome message
23      void processGrades() const; // perform operations on the grade data
24      int getMinimum() const; // find the minimum grade in the grade book
25      int getMaximum() const; // find the maximum grade in the grade book
26      double getAverage( const std::array< int, tests > & ) const;
27      void outputBarChart() const; // output bar chart of grade distribution
28      void outputGrades() const; // output the contents of the grades array
29   private:
30      std::string courseName; // course name for this grade book
31      std::array< std::array< int, tests >, students > grades; // 2D array
32   }; // end class GradeBook

 1   // Fig. 7.23: GradeBook.cpp
 2   // Member-function definitions for class GradeBook that
 3   // uses a two-dimensional array to store grades.
 4   #include <iostream>
 5   #include <iomanip> // parameterized stream manipulators
 6   using namespace std;
 7
 8   // include definition of class GradeBook from GradeBook.h
 9   #include "GradeBook.h" // GradeBook class definition
10
11   // two-argument constructor initializes courseName and grades array
12   GradeBook::GradeBook( const string &name,
13      std::array< std::array< int, tests >, students > &gradesArray )
14      : courseName( name ), grades( gradesArray )
15   {
16   } // end two-argument GradeBook constructor
17
18   // function to set the course name
19   void GradeBook::setCourseName( const string &name )
20   {
21      courseName = name; // store the course name
22   } // end function setCourseName
23
24   // function to retrieve the course name
25   string GradeBook::getCourseName() const
26   {
27      return courseName;
28   } // end function getCourseName
29
30   // display a welcome message to the GradeBook user
31   void GradeBook::displayMessage() const
32   {
33      // this statement calls getCourseName to get the
34      // name of the course this GradeBook represents
35      cout << "Welcome to the grade book for " << getCourseName() << "!"
36         << endl;
37   } // end function displayMessage
38
39   // perform various operations on the data
40   void GradeBook::processGrades() const
41   {
42      // output grades array
43      outputGrades();
44
45      // call functions getMinimum and getMaximum
46      cout << " Lowest grade in the grade book is " << getMinimum()
47         << " Highest grade in the grade book is " << getMaximum() << endl;
48
49      // output grade distribution chart of all grades on all tests
50      outputBarChart();
51   } // end function processGrades
52
53   // find minimum grade in the entire gradebook
54   int GradeBook::getMinimum() const
55   {
56      int lowGrade = 100; // assume lowest grade is 100
57
58      // loop through rows of grades array
59      for ( auto const &student : grades )
60      {
61         // loop through columns of current row
62         for ( auto const &grade : student )
63         {
64            // if current grade less than lowGrade, assign it to lowGrade
65            if ( grade < lowGrade )
66               lowGrade = grade; // new lowest grade
67         } // end inner for
68      } // end outer for
69
70      return lowGrade; // return lowest grade
71   } // end function getMinimum
72
73   // find maximum grade in the entire gradebook
74   int GradeBook::getMaximum() const
75   {
76      int highGrade = 0; // assume highest grade is 0
77
78      // loop through rows of grades array
79      for ( auto const &student : grades )
80      {
81         // loop through columns of current row
82         for ( auto const &grade : student )
83         {
84            // if current grade greater than highGrade, assign to highGrade
85            if ( grade > highGrade )
86               highGrade = grade; // new highest grade
87         } // end inner for
88      } // end outer for
89
90      return highGrade; // return highest grade
91   } // end function getMaximum
92
93   // determine average grade for particular set of grades
94   double GradeBook::getAverage( const array<int, tests> &setOfGrades ) const
95   {
96      int total = 0; // initialize total
97
98      // sum grades in array
99      for ( int grade : setOfGrades )
100        total += grade;
101
102     // return average of grades
103     return static_cast< double >( total ) / setOfGrades.size();
104  } // end function getAverage
105
106  // output bar chart displaying grade distribution
107  void GradeBook::outputBarChart() const
108  {
109     cout << " Overall grade distribution:" << endl;
110
111     // stores frequency of grades in each range of 10 grades
112     const size_t frequencySize = 11;
113     array< unsigned int, frequencySize > frequency = {}; // init to 0s
114
115     // for each grade, increment the appropriate frequency
116     for ( auto const &student : grades )
117        for ( auto const &test : student )
118           ++frequency[ test / 10 ];
119
120     // for each grade frequency, print bar in chart
121     for ( size_t count = 0; count < frequencySize; ++count )
122     {
123        // output bar label ("0-9:", ..., "90-99:", "100:" )
124        if ( 0 == count )
125           cout << "  0-9: ";
126        else if ( 10 == count )
127           cout << "  100: ";
128        else
129           cout << count * 10 << "-" << ( count * 10 ) + 9 << ": ";
130
131        // print bar of asterisks
132        for ( unsigned int stars = 0; stars < frequency[ count ]; ++stars )
133           cout << '*';
134
135        cout << endl; // start a new line of output
136     } // end outer for
137  } // end function outputBarChart
138
139  // output the contents of the grades array
140  void GradeBook::outputGrades() const
141  {
142     cout << " The grades are: ";
143     cout << "            "; // align column heads
144
145     // create a column heading for each of the tests
146     for ( size_t test = 0; test < tests; ++test )
147        cout << "Test " << test + 1 << "  ";
148
149     cout << "Average" << endl; // student average column heading
150
151     // create rows/columns of text representing array grades
152     for ( size_t student = 0; student < grades.size(); ++student )
153     {
154        cout << "Student " << setw( 2 ) << student + 1;
155
156        // output student's grades
157        for ( size_t test = 0; test < grades[ student ].size(); ++test )
158           cout << setw( 8 ) << grades[ student ][ test ];
159
160        // call member function getAverage to calculate student's average;
161        // pass row of grades as the argument
162        double average = getAverage( grades[ student ] );
163        cout << setw( 9 ) << setprecision( 2 ) << fixed << average << endl;
164     } // end outer for
165  } // end function outputGrades

 1   // Fig. 7.24: fig07_24.cpp
 2   // Creates GradeBook object using a two-dimensional array of grades.
 3   #include <array>
 4   #include "GradeBook.h" // GradeBook class definition
 5   using namespace std;
 6
 7   // function main begins program execution
 8   int main()
 9   {
10      // two-dimensional array of student grades
11      array< array< int, GradeBook::tests >, GradeBook::students > grades =
12         { 87, 96, 70,
13           68, 87, 90,
14           94, 100, 90,
15           100, 81, 82,
16           83, 65, 85,
17           78, 87, 65,
18           85, 75, 83,
19           91, 94, 100,
20           76, 72, 84,
21           87, 93, 73 };
22
23      GradeBook myGradeBook(
24         "CS101 Introduction to C++ Programming", grades );
25      myGradeBook.displayMessage();
26      myGradeBook.processGrades();
27   } // end main