«

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

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.

* 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:
> * 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?

On 5 Mar 2007 00:26:02 -0800 in comp.lang.c++, "ali"
<> wrote,
>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)
{ }