error

#include <iostream>
using namespace std;

class Person
{
     public:
        string profession;
        int age;

        Person(): profession("unemployed"), age(16) { }
        void display()
        {
             cout << "My profession is: " << profession << endl;
             cout << "My age is: " << age << endl;
             walk();
             talk();
        }
        void walk() { cout << "I can walk." << endl; }
        void talk() { cout << "I can talk." << endl; }
};

// MathsTeacher class is derived from base class Person.
class MathsTeacher : public Person
{
    public:
       void teachMaths() { cout << "I can teach Maths." << endl; }
};

// Footballer class is derived from base class Person.
class Footballer : public Person
{
    public:
       void playFootball() { cout << "I can play Football." << endl; }
};

int main()
{
     MathsTeacher teacher;
     teacher.profession = "Teacher";
     teacher.age = 23;
     teacher.display();
     teacher.teachMaths();

     Footballer footballer;
     footballer.profession = "Footballer";
     footballer.age = 19;
     footballer.display();
     footballer.playFootball();

     return 0;
}