Calling base class constructor from derived class Copy constructor

[ali]

Hi,

I am new to C++ and trying to understand how to work on Inheritance
and Operator overloading. I understand that the derived class can pass
the base class constructor in its constructor definition as following
code:

Car::Car(int id, int colorID, int type):Vehicle(id, colorID)
{
this->type = type;
}

What I am having difficulty with, is, how do I call the base class
constructor when writing the copy constructor for the derived class?

Example:

Car::Car(const Car &rhs)
{
//my code
}

Can I just add it as:

Car::Car(const Car &rhs):Vehicle(rhs.getID, rhs.getColor)
{
this->type = rhs.type;
}

I'm not sure of the above code copy constructor code accuracy, but
would appreciate some guidance.

Thank you!

Ali

[Ian Collins]

ali wrote:

Hi,

I am new to C++ and trying to understand how to work on Inheritance
and Operator overloading. I understand that the derived class can pass
the base class constructor in its constructor definition as following
code:

Car::Car(int id, int colorID, int type):Vehicle(id, colorID)
{
this->type = type;
}

Better to use an initialisation list:

ar::Car(int id, int colorID, int type)
: Vehicle(id, colorID), type(type) {}

What I am having difficulty with, is, how do I call the base class
constructor when writing the copy constructor for the derived class?

You can't. If you have some initialisation code you want to share
between constructors, and an initialise method and call it as required.

--
Ian Collins.

[Alf P. Steinbach]

* ali:

Hi,

I am new to C++ and trying to understand how to work on Inheritance
and Operator overloading. I understand that the derived class can pass
the base class constructor in its constructor definition as following
code:

Car::Car(int id, int colorID, int type):Vehicle(id, colorID)
{
this->type = type;
}

What I am having difficulty with, is, how do I call the base class
constructor when writing the copy constructor for the derived class?

Example:

Car::Car(const Car &rhs)
{
//my code
}

Can I just add it as:

Car::Car(const Car &rhs):Vehicle(rhs.getID, rhs.getColor)
{
this->type = rhs.type;
}

I'm not sure of the above code copy constructor code accuracy, but
would appreciate some guidance.

You can just add
Car::Car( Car const& other ): Vehicle( other )
{}

But that's what the compiler does for you if you don't declare a copy
constructor.

So you don't have to do anything.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

[Alf P. Steinbach]

* Alf P. Steinbach:

* ali:

>Hi,

I am new to C++ and trying to understand how to work on Inheritance
and Operator overloading. I understand that the derived class can pass
the base class constructor in its constructor definition as following
code:

Car::Car(int id, int colorID, int type):Vehicle(id, colorID)
{
this->type = type;
}

What I am having difficulty with, is, how do I call the base class
constructor when writing the copy constructor for the derived class?

Example:

Car::Car(const Car &rhs)
{
//my code
}

Can I just add it as:

Car::Car(const Car &rhs):Vehicle(rhs.getID, rhs.getColor)
{
this->type = rhs.type;
}

I'm not sure of the above code copy constructor code accuracy, but
would appreciate some guidance.

You can just add
Car::Car( Car const& other ): Vehicle( other )
{}

But that's what the compiler does for you if you don't declare a copy
constructor.

Uh, more members in Car, yes, didn't see that, should be

Car::Car( Car const& other ): Vehicle( other ), type( other.type )
{}

>
So you don't have to do anything.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

[David Harmon]

On 5 Mar 2007 00:26:02 -0800 in comp.lang.c++, "ali"
<al*************@gmail.comwrote,

>Can I just add it as:

Car::Car(const Car &rhs):Vehicle(rhs.getID, rhs.getColor)
{
this->type = rhs.type;
}

Preferable, if Vehicle has suitable copy constructor already

Car::Car(const Car &rhs)
: Vehicle(rhs),
type(rhs.type)
{ }