Three problems for c++

#ifndef PERSON_H #define PERSON_H #include <string> using namespace std; class Person { // data is private by default int age, gender; // male = 1 double weight, height, bmi; // kilograms, centimeters public: Person(); Person(int a, double w, double h, int g); int getAge() const {return age;} int getGender() const {return gender;} double getHeight() const {return height;} double getWeight() const {return weight;} void setBMI(double bmi) {this->bmi = bmi;} friend ostream& operator <<(ostream&, const Person&); }; #endif