class inheritance code not working - c++

Question

I have checked the class inheritance syntax and I'm pretty sure I don’t have a mistake ? did anything slip away from me ?
class person
{
public:
int personid;
string personname;
string personadress;
person( int apersonid, string apersonname, string apersonadress )//constructor
{
personid=apersonid;
personname=apersonname;
personadress=apersonadress;
}
int getpersonid()
{
return personid;
}
string getpersonname()
{
return personname;
}
string getpersonadress()
{
return personadress;
}
};
class employee: public person
{
public:
int commission;
employee(int _commission, int apersonid, string apersonname, string apersonaddress) : person(apersonid, apersonname, apersonaddress)
{
commission= _commission;
}
int getcommission()
{
return commission;
}
};
The error I'm getting is
Error 1 error C2512: 'person' : no appropriate default constructor
available

Answer 1

I suspect your problem is that your base class doesn't define a default constructor (with 0 arguments). Instead you have a constructor with multiple arguments.
person( int apersonid, string apersonname, string apersonadress )//constructor
{
personid=apersonid;
personname=apersonname;
personadress=apersonadress;
}
Your employee class inherits from person but it's constructor only takes one argument and does not initialize the base class using it's constructor.
employee( int _commission )
{
commission= _commission;
}
This is an issue b/c when you create an instance of the employee, it's trying to call the person class constructor as well. Since you don't have a default constructor (again, no arguments), you will need to explicitly call the person constructor in the employee constructor.
You have two options.
First, Modify the person constructor to take no arguments
person()
If you use this method, your signature for your employee class won't have to change.
Or you can Modify the employee constructor to take all the arguments the person constructor expects:
class employee: public person
{
public:
int commission;
employee(int _commision, int apersonid, string apersonname, string apersonadress ) : person(apersonId, apersonname, apersonadress)
{
commission = _commission;
}
int getcommission()
{
return commission;
}
};
In the constructor, the code after the colon (:) is a call to the person constructor using the arguments specified (apersonid, apersonname, apersonadress).
The employee constructor then assigns the value of _commission since it's scope is only relevant within the employee class.
Does that make sense?

Answer 2

In C++, if constructors are explicitly defined for a class, but they are all non-default, the compiler will not implicitly define a default constructor, leading to a situation where the class does not have a default constructor. You have defined a non default constructor in your class, this one :
person( int apersonid, string apersonname, string apersonadress )
So you need to define one default constructor yourself. E.g.
person() {}
Keep in mind, that in this case, when you construct an object of employee class the default constructor of person would be called. If that is not desired you need to call the non-default constructor of person in the constructor of employee.