Constructor for a class within a class - c++

Question

I have 2 classes, Date and Employee.
//Date
class Date
{
private:
int dd;
int mm;
int yy;
public:
Date (int, int, int);
void setDate (int, int, int);
int getDD();
int getMM();
int getYY();
};
//Employee
class Employee
{
private:
int ID;
string qualification;
double salary;
Date DOB;
Date dateJoined;
public:
Employee();
void setEmployee (int, string, double, Date, Date);
Date getDOB();
Date getDateJoined();
string getQualification();
void displayEmployee();
};
This is my constructor for Employee class.
Employee::Employee()
{
ID = 0;
qualification =" " ;
salary=0.0;
Date DOB();
Date dateJoined();
}
I got error C2512: 'Date' : no appropriate default constructor available.
How do I initialize DOB and dateJoined inside the Employee class?

Answer 1

The issue is that before the Employee constructor body is entered, all of the data members are constructed. In this instance, DOB and dateJoined need to be default-initialized, but there is no default constructor for your Date class. Your two main options are to add a default constructor for Date, or to initialize those members in the Employee constructor initializer list.
Option 1:
class Date
{
Date (); //define this somewhere
};
Option 2:
Employee::Employee() :
ID(0),
qualification(" "),
salary(0.0),
DOB(/*some data, maybe taken in as constructor args*/),
dateJoined(/*ditto*/)
{ }

Answer 2

Try this modification. You need a constructor Date():
class Date
{
private:
int dd;
int mm;
int yy;
public:
Date () {return;}
Date (int, int, int);
void setDate (int, int, int);
int getDD();
int getMM();
int getYY();
};
Another solution is:
Employee::Employee():
DOB(0,0,0),
dateJoined(0,0,0)
{
ID = 0;
qualification =" " ;
salary=0.0;
}