Need help understanding the syntax of C++ Classes - c++

Question

I've done the Harvard CS50 Course and worked with python a fair bit. I'm now doing a C++ course (Microsoft's) and the learning exercise has me creating a few classes. The exercise specifically tasks me to instantiate a few objects in main and return some values;
#include <iostream>
#include "School.h"
int main()
{
Student student1("Joe", "Bloggs", 31, "123 Fake Street", "London");
Student student2("Fred", "Adams", 24, "95 Something Avenue", "Manchester");
Student student3("John", "Doe", 90, "44a Old Man Lane", "Kettering");
Course course1("Introduction to Psychology");
course1.addStudent(student1);
course1.addStudent(student2);
course1.addStudent(student3);
Teacher teacher1("Helen", "Professorson", 48, "15 Teacher Way", "Kent");
course1.addTeacher(teacher1);
std::cout << course1.getCourseName() << std::endl;
teacher1.GradeStudent();
}
I'm using a header file and cpp file to define the classes, School.h:
#pragma once
#include <string>
class Person
{
public:
// Constructors and Destructors
Person();
Person(std::string, std::string); // First and Last Name
Person(std::string, std::string, int, std::string, std::string, std::string); // fName, lName, Age, Address, City, Phone
~Person();
// Member functions
std::string getFirstName();
void setFirstName(std::string);
std::string getLastName();
void setLastName(std::string);
int getAge();
void setAge(int);
std::string getAddress();
void setAddress(std::string);
std::string getCity();
void setCity(std::string);
std::string getPhone();
void setPhone(std::string);
private:
std::string _fName;
std::string _lName;
int _age;
std::string _address;
std::string _city;
std::string _phone;
};
class Student : public Person
{
public:
// Constructors and Destructors
// Member Functions
void SitInClass();
};
class Teacher : public Person
{
public:
// Member Functions
void SitInClass();
void GradeStudent();
};
class Course
{
public:
// Constructors and Desctructors
Course();
Course(std::string); // course name
~Course();
// Member functions
void addStudent(Student);
void addTeacher(Teacher);
// Getters and Setters
std::string getCourseName();
void setCourseName(std::string);
private:
// Member variables
std::string _courseName;
Student _students[30];
Teacher _teacher;
};
School.cpp:
#include "School.h"
#include <iostream>
#include <string>
// Constructors
Person::Person()
{
std::string _fName{};
std::string _lName{};
int _age{};
std::string _address{};
std::string _city{};
std::string _phone{};
}
Person::Person(std::string fName, std::string lName)
{
std::string _fName{ fName };
std::string _lName{ lName };
int _age{};
std::string _address{};
std::string _city{};
std::string _phone{};
}
Person::Person(std::string fName, std::string lName, int age, std::string address, std::string city, std::string phone)
{
std::string _fName{ fName };
std::string _lName{ lName };
int _age{ age };
std::string _address{ address };
std::string _city{ city };
std::string _phone{ phone };
}
// Destructor
Person::~Person()
{
}
std::string Person::getFirstName()
{
return this->_fName;
}
void Person::setFirstName(std::string fName)
{
this->_fName = fName;
}
std::string Person::getLastName()
{
return this->_lName;
}
void Person::setLastName(std::string lName)
{
this->_lName = lName;
}
int Person::getAge()
{
return this->_age;
}
void Person::setAge(int age)
{
this->_age = age;
}
std::string Person::getAddress()
{
return this->_address;
}
void Person::setAddress(std::string address)
{
this->_address = address;
}
std::string Person::getCity()
{
return this->_city;
}
void Person::setCity(std::string city)
{
this->_city = city;
}
std::string Person::getPhone()
{
return this->_phone;
}
void Person::setPhone(std::string phone)
{
this->_phone = phone;
}
void Student::SitInClass()
{
std::cout << "Sitting in main theater" << std::endl;
}
void Teacher::SitInClass()
{
std::cout << "Sitting at front of class" << std::endl;
}
void Teacher::GradeStudent()
{
std::cout << "Student Graded" << std::endl;
}
Course::Course()
{
Student* _students;
Teacher* _teacher;
std::string _name{};
}
Course::Course(std::string name)
{
Student* _students[30];
Teacher* _teacher;
std::string _name{ name };
}
Course::~Course()
{
}
void Course::addStudent(Student student)
{
// TODO: Loop through _students and insert new student in
}
void Course::addTeacher(Teacher teacher)
{
this->_teacher = &teacher;
}
std::string Course::getCourseName()
{
return this->_name;
}
void Course::setCourseName(std::string name)
{
this->_name = name;
}
I actually haven't been taught inheritance yet, but since both Student and Teacher needed the same variables (name, age, address etc.) I decided it'd be sensible.
Having a few problems though:
My instantiations of Student and Teacher in main.cpp aren't correct. I think because they are inheriting from Person(?). How do I create a constructor within these derived classes? I googled this but the solutions didn't seem to work.
The Course Class requires an array of Students. Do I have to specify a size of the array in the header file? It seems silly that I've specified 30 in both the header file and the cpp file, but VSstudio complains if I don't.
I'm using strings here. I have previously learned from a different course about char* and memory regarding strings. How many chars are assigned to all of these string class variables? If I instantiate a Students with name "Joe" and then want to later change his name to "Joseph" using student1.SetFirstName, is that going to cause segmentation faults?

Answer 1

Thanks, I figured it out mostly...
I needed to create constructors in Student and Teacher with the same input variables as the Person class, and then call the Person constructor in the Student consturctor:
Student::Student()
{
}
Student::Student(std::string fName, std::string lName)
: Person(fName, lName)
{
}
Student::Student(std::string fName, std::string lName, int age, std::string address, std::string city, std::string phone)
: Person(fName, lName, age, address, city, phone)
{
}
You do not need to specify array size in the constructor:
Header file looks like this:
class Course
{
...
private:
// Member variables
std::string _name;
Student* _students[30];
Teacher* _teacher;
};
And the constructor looks like this:
Course::Course()
: _students{ 0 }, _teacher{ 0 }, _name{}
{
}
To initialise every array item to 0.
Not so sure on still...