Question

I’m doing a Systems Programming homework.
I have to implement a university.
I have a Course class, with child classes ComputerScience courses class, PG courses class, and Elective courses class.

class Course
{
public:
    virtual void teach();
    virtual void reg(Student &s)=0;
    std::string getName();
    std::string getDepartment();
    int getSemester();
    int getMinGrade();
    void addStudent(Student *s);
    void removeStudent(Student *s);

protected:
    std::string _department;
    std::string _name;
    int _semester;
    int _minGrade;
    std::vector<Student*> studentsList;  
};

class CSCourse : public Course
{
public:
    CSCourse();
    CSCourse(std::string department, std::string name, int semester, int mingrade);
    ~CSCourse();
    std::string getName();
    std::string getDepartment();
    int getSemester();
    int getMinGrade();
    void addStudent(Student *s);
    void removeStudent(Student *s);
};

(PG courses and Elective courses child classes are the same)
In the functions in the Course class (which are not void, like getSemester and such..) I just do dynamic_cast to figure what type of course is it.

I am having this problem:

coursesVector is:

std::vector<Course*> coursesVector

and dp variable is a string containing either CS, PG or Elective. In the main, I do this:

if (dp == "CS")
{
    CSCourse *csCourse = new CSCourse(dp, name, semester, minGrade);
    coursesVector.push_back(csCourse);
}

it gives me “Cannot allocate object of abstract type CS Course”.
Same goes for PG and Elective!

But, in my definiton of hte class, CS course is not abstract!

Answer 1

The CSCourse class is abstract.

You have declared a pure virtual function reg in Course, but not provided an implementation in CSCourse.

You compiler undoubtedly told you exactly this as well.