Creation and use of a dynamic array in C++ - c++

Question

I'm trying to finish a C++ school assignment and I have a question that I have an issue that may be simple. I have constructed all the files (more than below which felt was unnecessary to add) from scratch and I am left scratching my head. I'm told to create a private dynamic array of objects that will be defined by user input. This will be in the "student.cpp" file. This dynamic array is to create the objects that will operate the "course.cpp" file. I have attempted a large series of workarounds, but have not found the answer and expect the answer to be obvious. Here is the trimmed down version of my code. I also commented where the issue is in the student.cpp file and the other points of possible issue.
Any suggestions will be appreciated. I manually typed this again, so if it appears there was a typo, my apologies in advance. I will edit if I notice anything after the initial post.
//source.cpp
#include <iostream>
#include "student.h"
using namespace std;
void main() {
student stu;
stu.printRecord();
}
//student.h
#ifndef STUDENT_H
#define STUDENT_H
#include<iostream>
#include<string>
#include "course.h"
using namespace std;
class student{
public:
student();
void printRecord();
~student();
private:
string name;
int numCourses;
course* stuCourses; //possible source of error
};
#endif
//student.cpp
#include "student.h"
student::student(){
cout << "enter name: ";
getline(cin,name);
cout << "Enter the number of courses the student is taking: ";
cin >> numCourses;
course* stuCourses= new course[numCourses]; //possible source of error (now this->stuCourses = new course[numCourses];)
}
void student::printRecord(){
cout << endl << name << endl;
course::printCourse(); //Error at this point
}
//course.h
#ifndef COURSE_H
#define COURSE_H
#include <iostream>
using namespace std;
class course{
public:
course();
void printCourse();
~course();
private:
string title;
};
#endif
//course.cpp
#include <iostream>
#include "course.h"
course::course(){
cout << "Title: ";
cin >> title;
}
void course::printCourse(){
cout <<title;
}
course::~course(){}
Again, any help is appreciated. Thanks for looking even if you don't respond.

Answer 1

class course{
public:
course();
void printCourse();
~course();
private:
string title;
};
Here you defined printCourse as a non-static-method of the class course.
But where the error occurs: course::printCourse() you're trying to execute a static method of the class Course. If you don't know what I'm talking about here is a short summary (but i recommend reading about the differences between static and non static methods):
A static method works without an instance of the class. This is commonly used on singletons which are by design "just one single object". This could be for example a global ID-Counter for the students:
class StudentIdManager
{
static int num_students = 0;
public:
static int getNextStudentId()
{
return num_students++;
}
}
You can now get the next unique id for a student by calling StudentIdManager::getNextStudentId() without an actual object. You could call it a "class function". Not an "object function".
A static class is obviously not suitable for your course, so it makes sense for your to implement it like you did.
However, you have to call it on an actual object. The difficulty is to find each object in the dynamically allocated array, but you should have every info you need. In the end it would look something like this:
void student::printRecord()
{
cout << endl << name << endl;
for (size_t i = 0u; i < numCourses; i++)
{
// here you're now calling the method printCourse on an actual course as intended instead of a static class
stuCourses[i]->printCourse();
}
}
However I also find it weird that you have to implement this. A simple std::array<course, numCorses> for a fixed number of courses, or a std::vector<course> for a variable number of courses would make the code way more readable, safe and extensible.
What you're doing here would is a nice task for C to get used to the Von Neuman Architecture.
But not for C++. It's not the same. Sadly for most teachers C++ is "C with classes" which is just wrong on so many levels. All the features C++ added where there for you to not write code like your teacher wants.

Answer 2

Instead of:
course* stuCourses= new course[numCourses];
Can use:
this->stuCourses = new course[numCourses];
Or even:
stuCourses = new course[numCourses];