$6\mathrm{.}12\mathrm{.}1$: LAB: Course gradebook with unordered$\_$map

Step $1$: Inspect the Gradebook abstract base class

The read$-$only Gradebook.h file has a declaration for the Gradebook abstract base class. The Gradebook class stores a collection of entries for a course. Conceptually, a gradebook entry is an $($assignment name, student ID$,$ score$)$ triplet. Each entry's assignment name is a string, student ID is an integer, and score is a double. A score is entered into the gradebook via the SetScore$()$ function.

The Gradebook class has six pure virtual functions that must be implemented in an inheriting class.

Step $2$: Add member variables to the CourseGradebook class

The CourseGradebook class inherits from Gradebook and is declared in CourseGradebook.h$.$ Inspect each function that must be implemented. Choose one or more member variables to store gradebook data, and add the member variables to the CourseGradebook class. Several options exist, so grading does not analyze the choice of member variables.

Step $3$: Implement CourseGradebook's SetScore$()$ and GetScore$()$ functions

Implement the SetScore$()$ function to enter a single entry into the gradebook. SetScore$()$ has parameters for the assignment name, student ID$,$ and score. How the entry is stored depends on the member variables chosen in step $2.$

Implement the GetScore$()$ function to get a single score from the gradebook. GetScore$()$ has parameters for the assignment name and student ID$,$ and returns a double for the corresponding score. NAN is returned if no such entry exists in the gradebook.

Code in main.cpp calls TestGetScoreAndSetScore$()$ to test both functions. Run your program and ensure that the test passes before proceeding further.

Step $4$: Implement the remaining CourseGradebook functions

Implement the remaining functions according to the specifications below.

GetAssignmentScores$()$ takes a string for the assignment name and returns an unordered$\_$map that maps a student ID to the student's corresponding score for the assignment. An entry exists in the returned map only if a score has been entered with the SetScore$()$ function. An empty map is returned if no such assignment exists in the grade book.

GetSortedAssignmentNames$()$ returns a vector with all distinct assignment names, sorted in ascending order.

GetSortedStudentIDs$()$ returns a vector with all distinct student IDs, sorted in ascending order.

GetStudentScores$()$ gets all scores that exist in the gradebook for the student whose ID equals the function parameter. Scores are returned as an unordered$\_$map that maps an assignment name to the student's corresponding score for that assignment.

If needed, implement CourseGradebook's destructor to free any dynamically allocated content stored in the gradebook.

#ifndef COURSEGRADEBOOK$\_$H

#define COURSEGRADEBOOK$\_$H

#include

#include "Gradebook.h$"$

class CourseGradebook : public Gradebook $\{$

protected:

$//$ TODO: Type your code here

public:

virtual ~CourseGradebook$()\{$

$//$ TODO: Type your destructor code here, if needed

$\}$

std::unordered$\_$map GetAssignmentScores$($

std::string assignmentName$)$ override $\{$

$//$ TODO: Type your code here $($remove placeholder line below$)$

return std::unordered$\_$map$()$;

$\}$

double GetScore$($std::string assignmentName, int studentID$)$ override $\{$

$//$ TODO: Type your code here $($remove placeholder line below$)$

return NAN;

$\}$

std::vector GetSortedAssignmentNames$()$ override $\{$

$//$ TODO: Type your code here $($remove placeholder line below$)$

return std::vector$()$;

$\}$

$//$ GetSortedStudentIDs$()$ returns a vector with all distinct student IDs,

$//$ sorted in ascending order.

std::vector GetSortedStudentIDs$()$ override $\{$

$//$ TODO: Type your code here $($remove placeholder line below$)$

return std::vector$()$;

$\}$

$//$ GetStudentScores$()$ gets all scores that exist in the gradebook for the

$//$ student whose ID equals the studentID parameter. Scores are returned as

$//$ an unordered$\_$map that maps an assignment name to the student's

$//$ corresponding score for that assignment.

std::unordered$\_$map GetStudentScores$($

int studentID$)$ override $\{$

$//$ TODO: Type your code here $($remove placeholder line below$)$

return std::unordered$\_$map$()$;

$\}$

void SetScore$($std::string assignmentName, int studentID, double score$)$ override $\{$

$//$ TODO: Type your code here

$\}$

$\}$;

#endif