Дейтел. Помощь в решении задач из книги

#include <string>
 
using namespace std;
 
class GradeBook
{
public:
    GradeBook(string);
    void setCourseName(string);
    string getCourseName();
    void setTeacherName(string);
    string getTeacherName();
    void displayMessage();
private:
    string courseName;
    string teacherName;
};

#include <iostream>
#include "GradeBook.h"
 
using namespace std;
 
GradeBook::GradeBook(string name)
{
    setCourseName(name);
    setTeacherName(name);
}
 
void GradeBook::setCourseName(string name)
{
    courseName = name;
}
 
 
string GradeBook::getCourseName()
{
    return courseName;
}
 
void GradeBook::setTeacherName(string name)
{
    teacherName = name;
}
 
string GradeBook::getTeacherName()
{
    return teacherName;
}
 
void GradeBook::displayMessage()
{
    cout << "Welcome to the grade book for\n" << getCourseName()
         << "!" << endl;
    cout << "This course is presented by: " << getTeacherName()
         << "!" << endl;
}

#include <iostream>
#include "GradeBook.h"
 
using namespace std;
 
int main()
{
    GradeBook gradeBook1 ("CS101 Introduction to Programming in C++", "Masha");
    GradeBook gradeBook2 ("CS102 C++ Data Structures", "Vasia");
 
    gradeBook1.displayMessage();
    gradeBook2.displayMessage();
 
    return 0;
}

public:
    GradeBook(string name, string name1);

GradeBook::GradeBook(string name, string name1)
{
    setCourseName(name);
    setTeacherName(name1);
}

void GradeBook::setTeacherName(string name1)
{
    teacherName = name1;
}

GradeBook::GradeBook( сщтые string &courseName, const string &teacherName ) :
   courseName( courseName ),  teacherName( teacherName )
{
}