compile.txt

~/Projects/c++test # clang++ -std=c++11 test.cpp
test.cpp:52:18: error: variable type 'AbstractPerson' is an abstract class
  AbstractPerson x = Teacher("Thomas");
                 ^
test.cpp:19:20: note: unimplemented pure virtual method '_getName' in 'AbstractPerson'
    virtual string _getName() = 0;
                   ^
test.cpp:20:18: note: unimplemented pure virtual method '_isTeacher' in 'AbstractPerson'
    virtual bool _isTeacher() = 0;
                 ^
1 error generated.

interface_test.cpp

#include <string>
#include <iostream>

using namespace std;

class AbstractPerson {
  public:
    string getName() {
      return this->_getName();
    }

    bool isTeacher() {
      return this->_isTeacher();
    }

  private:
    virtual string _getName() = 0;
    virtual bool _isTeacher() = 0;
};

class Person : public AbstractPerson {
  public:
      Person(string name) : name(name) {};

  private:
    string name;

    string _getName() {
      return this->name;
    }

    bool _isTeacher() {
      return false;
    }

  private:
};

class Teacher : public Person {
  public:
    Teacher(string name) : Person(name) {};

  private:
    bool _isTeacher() {
      return true;
    }
};

int main() {
  AbstractPerson x = Teacher("Thomas");

  if (x.isTeacher()) {
    cout << x.getName() << " is a teacher." << endl;
  }

  return 0;
}