Composition

#include <iostream>
#include <string>

using namespace std;
//birthday class created
class birthday{
private:
    int month;
    int day;
    int year;
public:
    birthday(int m, int d, int y){
        month=m;
        day=d;
        year=y;
    }
    void printDate();
};
void birthday :: printDate(){
    cout << month << " " << day << " " << year << endl;
}
// people class created
class people{
private:
    string name;
    birthday dateOfBirth;
public:
    people(string x, birthday bo)
    :name(x),dateOfBirth(bo){   // member initialization
    }
    void printInfo();

};
void people::printInfo(){
    cout << name << " was born on ";
    dateOfBirth.printDate();

}
int main(){
    birthday jon(4, 13, 108);
    people lyanna("jon the stargaryen", jon);
    lyanna.printInfo();
    return 0;
}