C / C++ / MFC

Re: class initialize problem

10-Mar-02 22:53

Use CreateFile("LPT1",...) and then regular ReadFile and WriteFile on the handle obtained. Check Parallel Port Central for further info.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

class initialize problem

10-Mar-02 22:24

how can i initialize a indirect bass class using constructor?
example

class A{
public:
int i1
A(int i){i1=i;};
};

class B:public A{
public:
int i2
B(int i){i2=i;}
};

class C:public B{
public:
int i3
C(int i){i3=i;}
};

main(){
C* p = new C(1) // how to initialize A::i1 and B::i2 here?
}

Joaquín M López Muñoz10-Mar-02 22:25

Re: class initialize problem

10-Mar-02 22:25

C and B have to provide the means to initialize base classes B and A, respectively. You can write constructors like this:

class B:public A{
public:
B(int i,int j):A(j){i2=i;} // initialize base class A with j, the rest as before
...
};

class C:public B{
public:
C(int i,int j,int k):B(j,k){i3=i;}
...
};
...
main(){
C* p = new C(1,2,3); // i3==1, i2==2, i1==3
}

Hope you get the idea.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

10-Mar-02 22:45

It there no direct way to initialize multi-inherit base class?
I get your point, but i guess such a mature language like c++ should have more effect way to do that.

thank u after all.

Re: class initialize problem

Joaquín M López Muñoz10-Mar-02 23:09

10-Mar-02 23:09

No, the only way to initialize base class(es) of a given class is by using the constructors provided by the class¹. This has some motivation, though: it is the responsibilty of a class to maintain internal consistency among its members and base classes, so it is wise to let this class restrain construction of base classes (and even access, for that matter) to implement the particular logic suitable for the context in which these subobjects are used.

¹When defining a ctor for a class, under certain special circumnstances (namely virtual derivation) you can directly call constructors from classes that are not direct bases but rather lie farther up the hierarchy. This is a rather messy subject, though, and often it doesn't work as first expected.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

MFC & Flowcharts

10-Mar-02 21:50

Please help me ! (and please excuse my poor english)

I would like to find a FREE method to use flow charts in MFC applications. This method can be a CView derived class or an ActiveX control.
If you know this type of control/class please answer to this thread because I don't want to develop a complete class if an equivalent exists.

Thanks a lot !!!

jpeg

Aaargh!! SS_NOTIFY

Rickard Andersson²⁰10-Mar-02 21:27

10-Mar-02 21:27

How can I set SS_NOTIFY to a dynamic created control??????????????

------------------------------------
Rickard Andersson, Suza Computing
ICQ#: 50302279
I'm from the winter country SWEDEN!

------------------------------------

Joaquín M López Muñoz10-Mar-02 21:36

10-Mar-02 21:36

I'd say you only need to add this flag to the dwStyle parameter when calling CControl::Create.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Rickard Andersson²⁰10-Mar-02 21:40

10-Mar-02 21:40

Damn, I post messages here as fast as I get stucked... Smile | :)

I realy have to calm down..........

SORRY Guy's!!!

------------------------------------
Rickard Andersson, Suza Computing
ICQ#: 50302279
I'm from the winter country SWEDEN!

------------------------------------

Nish Nishant10-Mar-02 21:36

Nish Nishant

10-Mar-02 21:36

Rickard Andersson wrote:
How can I set SS_NOTIFY to a dynamic created control??????????????

Try ModifyStyle. Might work. Not sure. Let me know.

Nish

p.s. 4 sentences in 1 line. Cryptic eh? Smile | :)

Bow wow wow,
Yippee yo yippee yay,
My miniputt high,
Is now 30 yay.

Rickard Andersson²⁰10-Mar-02 21:40

10-Mar-02 21:40

Damn, I post messages here as fast as I get stucked... Smile | :)

Nish Nishant10-Mar-02 21:45

Nish Nishant

10-Mar-02 21:45

Rickard Andersson wrote:
I realy have to calm down..........

SORRY Guy's!!!

No problem. It's fun Smile | :)

Nish

Bow wow wow,
Yippee yo yippee yay,
My miniputt high,
Is now 30 yay.

Mazdak10-Mar-02 21:40

Mazdak

10-Mar-02 21:40

Nish [BusterBoy] wrote:
p.s. 4 sentences in 1 line. Cryptic eh?

Whats that Nish? Smile | :)

Mazy

"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975

Nish Nishant10-Mar-02 21:43

Nish Nishant

10-Mar-02 21:43

Well I typed :-

"Try ModifyStyle. Might work. Not sure. Let me know."

That's 4 separate sentences all in one single HTML line.
I found that funny Smile | :)

Nish

p.s. almost like a 20th century telegram eh?

Bow wow wow,
Yippee yo yippee yay,
My miniputt high,
Is now 30 yay.

Joaquín M López Muñoz10-Mar-02 21:55

10-Mar-02 21:55

This reminds me of the (according to Guiness' Records Book) shortest mail correspondence ever, which took place between some novelist whose name I don't care to remember and his editor. The former, after submitting his novel to the press, went to the country for a small vacation, and some days later he was curious as to how the novel was selling. He wrote this letter to the editor:

and the answer was

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Mazdak10-Mar-02 22:02

Mazdak

10-Mar-02 22:02

lol

Mazy

"So,so you think you can tell,
Heaven from Hell,
Blue skies from pain,...
How I wish,how I wish you were here."
Wish You Were Here-Pink Floyd-1975

Is allocated`?????

Rickard Andersson²⁰10-Mar-02 20:39

10-Mar-02 20:39

How can check if I've allocated memory to a variable??

------------------------------------
Rickard Andersson, Suza Computing
ICQ#: 50302279
I'm from the winter country SWEDEN!

------------------------------------

Jeason Zhao10-Mar-02 20:43

Jeason Zhao

10-Mar-02 20:43

check the return value of alloc();)

Please pardon my weak English!

Rickard Andersson²⁰10-Mar-02 21:17

10-Mar-02 21:17

but if I use 'new'? Smile | :)

------------------------------------
Rickard Andersson, Suza Computing
ICQ#: 50302279
I'm from the winter country SWEDEN!

------------------------------------

Joaquín M López Muñoz10-Mar-02 21:18

10-Mar-02 21:18

Initialize your pointers to NULL and reset them again to NULL after deleteing them. This way you'll always know when they are pointing to allocated memory.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Rickard Andersson²⁰10-Mar-02 21:26

10-Mar-02 21:26

Joaquín M López Muñoz wrote:
Initialize your pointers to NULL and reset them again to NULL after deleteing them

ehm.. like this:

delete m_pMyCtl;
m_pMyCtl = NULL;
m_pMyCtl = NULL;

dah... Is it right?

------------------------------------
Rickard Andersson, Suza Computing
ICQ#: 50302279
I'm from the winter country SWEDEN!

------------------------------------

Joaquín M López Muñoz10-Mar-02 21:30

10-Mar-02 21:30

Sort of, tha last m_pMyCtl = NULL is redundant (or the first one, if you prefer Smile | :)

)

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo

Rickard Andersson²⁰10-Mar-02 21:33

10-Mar-02 21:33

Well, I tried checkd if my pointer was NOT NULL. and then delete myptr and then myptr = NULL but the compiler said something with memory problems... bla bla... damn I can't remember the debug error...

------------------------------------
Rickard Andersson, Suza Computing
ICQ#: 50302279
I'm from the winter country SWEDEN!

------------------------------------

Joaquín M López Muñoz10-Mar-02 21:38