Re: [Dev-C++] Structures and Arrays and Pointers, Oh My!

[David M. <ci...@ya...>]

--- OROSZI_Balázs <or...@vp...> wrote:
> David McKen wrote:
> > Ok, I am having trouble using the above 3 together.
> >  
> > Slay_msg is a array of pointers to characters (strings)
> > struct pc_data {
> >   char * slay_msg[3];
> > }
> >  
> > //a pointer to pc_data is a member of the char_data
> struct.
> > struct char_data {
> >    ...
> >    pc_data *  pcdata;
> > }
> >  
> > //A pointer is declared of type char_data and
> initalized to the required 
> > values.
> > char_data * ch = new char_data; //Assume everything has
> been initalized.
> >  
> > My question is: How do I access the strings in the
> array slay_msg?
> 
> First of all, this is NOT a pure C program, as you are
> using "new", and 

My mistake malloc is used (I just used new for simplicity)

> that is only in C++.
> Do you EXPLICITLY create pcdata inside ch? As it will
> *not* be created.
> This is what I have done, and this works:
> 
> int main()
> {
>    char_data *ch = new char_data;
>    ch->pcdata = new pc_data;
>    ch->pcdata->slay_msg[1] = "Dead!";
>    printf("%s\n",ch->pcdata->slay_msg[1]);
>    delete ch;
>    return 0;
> }
> 
> Another note: slay_msg is an array of pointers, so you
> can only assign 
> values to them, not copy into them!
> 
> Access is as follows: ch->pcdata->slay_msg[<index here>],
> what you used! 
> Your problem is at creation I guess. You don't initialize
> pcdata I 
> think. You must explicitly create it, as it's constructor
> won't get 
> called (it is a pointer)!

I see, I will have to go to check that.
 
> But again, I WARN you! This is *not* pure C! C doesn't
> have "new", and 
> structs should be typedefed, so you can create variables
> without writing 
> the "struct" word before the declaration. ("struct
> char_data ch;" would 
> be needed in pure C)
 
Those few code snippets are what poped into my head to
explain my problem.

> Try to compile it with gcc, not g++. It won't :)
> 
> --
> Greetings,
>    Balázs

Cool, This explains alot.
Thank you.
David Mcken


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