C++ classes and pointers (Me again with my Tile classes :D)

Question

Link to my last topic: C++ class forward declaration

Now main thing:

I decided to change all returned types to pointers to avoid memory leaks, but now I got:

27 C:\Dev-Cpp\Projektyyy\strategy\Tiles.h ISO C++ forbids declaration of `tile' with no type 
27 C:\Dev-Cpp\Projektyyy\strategy\Tiles.h expected `;' before "tick"

Its only in base class, everything else is ok... Every function in tile class which return *tile has this error...

Some code:

class tile
{
      public:
          double health;
          tile_type type;
          *tile takeDamage(int ammount) {return this;};
          *tile onDestroy() {return this;};
          *tile onUse() {return this;};
          *tile tick() {return this};
          virtual void onCreate() {};
};

You don't "avoid memory leaks" by "changing all returned types to pointers". You avoid them by writing correct code. — Kerrek SB, Feb 02 '12 at 20:45
@kittyPL: That's debatable and impossible to tell from your code. Modern C++ usually contains hardly any naked pointers or `new` expressions at all, and `delete` never, so I wouldn't bank on it that you're up to a good solution... — Kerrek SB, Feb 02 '12 at 20:47
@gamernb when I read your comment I thought "pff, im not so stupid...", but then looked in my code and BANG! :D Double facepalm for me, would be a vote up and accept for you :) — noisy cat, Feb 02 '12 at 20:48
@kittyPL I highly doubt that, but even if that is true, you using pointers will most likely lead [to more memory leaks](http://stackoverflow.com/questions/8839943/why-is-it-a-memory-leak-what-could-i-catch-if-i-shall-use-such-things-in-c/8840302#8840302), not avoid them. — R. Martinho Fernandes, Feb 02 '12 at 20:49
@ildjarn if you mean that I have inline functions, you are right, but it's only a base class (Im going to make it virtual) and subclasses have separate files for headers and definitions :) — noisy cat, Feb 02 '12 at 20:50
@kittyPL : No, I mean that you certainly do not need to have pointers to have correct code. (And _most_ memory leaks are caused by _using_ pointers, not by not using them...) — ildjarn, Feb 02 '12 at 20:52
@ildjarn Well, read the topic in link and try to think a better way to change class... — noisy cat, Feb 02 '12 at 21:53
@kittyPL : Armen's answer (which _you_ selected as the correct answer) already shows you the way to change the class -- notice that he doesn't use any pointers! — ildjarn, Feb 02 '12 at 21:56
@ildjarn sorry, I dont understand. I have 2 separate classes in his answer. Im going to have tile foo[X][Y] tab, and I have tile children classes. I want to change tile_tree into tile_tree_apple (when apples grow up)... How to do that? I decided to use return value to assign new object to my map tab. Do you know any better way? — noisy cat, Feb 02 '12 at 22:01
@ildjarn well, answer please, Im not sure about my decision. Still can change everything... :D — noisy cat, Feb 02 '12 at 22:21
@kittyPL : I don't understand your last question at all, so I can't answer it, sorry. I'm only arguing against use of pointers. — ildjarn, Feb 02 '12 at 22:22

score 5 · Accepted Answer · edited Feb 02 '12 at 20:48

5

You're missing a semi-colon on the return for tick, and the * goes after the type when declaring pointers:

tile* tick() {return this;};

edited Feb 02 '12 at 20:48

R. Martinho Fernandes

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answered Feb 02 '12 at 20:42

wocoburguesa

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Also put the * after tile, like so: tile * name; – wocoburguesa Feb 02 '12 at 20:47

score 2 · Answer 2 · edited Feb 02 '12 at 21:23

class tile
{
      public:
          double health;
          tile* takeDamage(int ammount) {return this;}
          tile* onDestroy() {return this;}
          tile* onUse() {return this;}
          tile* tick() {return this;}
          virtual void onCreate() {}
};

Here you go. I removed tile_type since I don't know what that is. Probably an enum. Apart from that you had lots of issues with semi-colons.

C++ classes and pointers (Me again with my Tile classes :D)

2 Answers2