Constructor in C++

[Allerdyce.John@gmail.com]

Hi,

I have 2 classes:

class A {
public:
A();
A(int i);
};

class B: public A {
pubilc:
B(int i);
};

If I don't have constructor B(), does it call A() automatically?

Can I do this:
B b; // B does not have default constructor but A has.

[Alf P. Steinbach]

Re: Constructor in C++

* Allerdyce.John@ gmail.com:[color=blue]
> Hi,
>
> I have 2 classes:
>
> class A {
> public:
> A();
> A(int i);
> };
>
> class B: public A {
> pubilc:[/color]

See <url: http://www.google.com/search?q=pubilc >.

[color=blue]
> B(int i);
> };
>
> If I don't have constructor B(), does it call A() automatically?[/color]

If you don't have a constructor B() it doesn't exist; C++ only generates
one for you if you don't declare any constructors at all.

[color=blue]
> Can I do this:
> B b; // B does not have default constructor but A has.[/color]

Nope.


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Q: Why is it such a bad thing?
A: Top-posting.
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[Allerdyce.John@gmail.com]

Re: Constructor in C++

If I have
class A {
public
A(int i);
}

public B{
public:
virtual void abstractFuncito n = 0;
}

public C{
public:
C(int i);
};

how can I call A' constructor A(int i) from C(int i).

I try
C::C(int i): A(i) {
}
it does not compile.

[Alf P. Steinbach]

Re: Constructor in C++

* Allerdyce.John@ gmail.com:[color=blue]
> If I have
> class A {
> public
> A(int i);
> }
>
> public B{
> public:
> virtual void abstractFuncito n = 0;
> }
>
> public C{
> public:
> C(int i);
> };
>
> how can I call A' constructor A(int i) from C(int i).
>
> I try
> C::C(int i): A(i) {
> }
> it does not compile.[/color]

C does not derive from A.



--
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?

[Victor Bazarov]

Re: Constructor in C++

Allerdyce.John@ gmail.com wrote:[color=blue]
> If I have
> class A {
> public
> A(int i);
> }[/color]
;[color=blue]
>
> public B{
> public:
> virtual void abstractFuncito n = 0;[/color]

virtual void pureFunction() = 0;
[color=blue]
> }[/color]
;[color=blue]
>
> public C{
> public:
> C(int i);
> };
>
> how can I call A' constructor A(int i) from C(int i).
>
> I try
> C::C(int i): A(i) {
> }
> it does not compile.
>[/color]

You need to derive 'C' from 'A' first to do that.

V
--
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