passing in a class instance as another class parameter

Question

Course newCourse(id,instructor[id2],name,dept);
Course::courseList.insert(std::pair<int,Course>(id,newCourse));

This is the part of the code where I call the constructor of the course class. The instructor[id2] is how I thought it might work but it doesn't.

 Course(int courseId, Instructor instructor, string courseName, string   dept)
 :courseId(courseId),instructor(instructor),courseName(courseName),dept(dept)
 {
 };

This is the code snippet from the class definition. As you can see 3 of the arguments are an int, and 2 strings. I know how to pass those in fine but its the Instructor instructor argument that I am stuck on.

The Instructor class has each person's info stored in a map with an int as the key. The file I am reading from the build the course class uses an int to relate the course to an instructor. I figured I'd use the int and look into the instructor map to pull out the right person's name but I keep getting undefined function errors.

Example from the file:

0,0,Science,Dept
the first 0 s the course ID number and the second is the instructor ID number.

Edit: different method appears to be the same type of call

code from the method in question

224             string myText(line);
225             istringstream iss(myText);
226             if (!(iss>>id)) id = 0;
227             iss.ignore(1,',');
228             if (!(iss>>id2)) id2 = 0;
229             cout<<"id: "<<id<<" id2: "<<id2<<endl;
230             Enrollment newEnrollment(Course::courseList[id], Student::studentList[id2]);

The constructor declaration:

 87         Enrollment(Student student,Course course):student(student),course(course){}

error:

:In static member function `static int Enrollment::loadEnrollment()

230: error: no matching function for call to `Enrollment::Enrollment(Course&, Student&)'

81: error: candidates are: Enrollment::Enrollment(const Enrollment&)

88: error: Enrollment::Enrollment()

87: error: Enrollment::Enrollment(Student, Course)

Answer 1

You are trying to access the operator[] on a variable named instructor. This variable does not have this operator defined. This is what gives you the compile error.

The loaded instructors are found in the Instructor::instructorList variable, as is shown in the code that loads the instructors from file.

To resolve this error you must change the line containing instructor[id2] to use the list instead:

Course newCourse(id,Instructor::instructorList[id2],name,dept);