Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Simmura McCrea]

I'm trying to alter attributes of the objects themselves.

[RulerOfNothing]

In that case you could use Object** objects in the parameters (or something along those lines), and use objects to access an object. Keep in mind that objects is going to be a pointer.

[Simmura McCrea]

I don't follow what you mean there. Do you mean just to change the parameters to (Object** objects[]) or something more complicated?

[RulerOfNothing]

Well, you could go with Object* objects[], but a C++ compiler doesn't distinguish between that and Object** objects.

[Simmura McCrea]

Oh. That's like the first thing I tried. Still no dice. Tells me there's no matching function for the call.

[RulerOfNothing]

Alright then. Firstly: what is the function signature in question? Secondly: can you show me the definition of the array in your code?

[Simmura McCrea]

Code: [Select]

bullet* Bullets[MAX_BULLETS];MAX_BULLETS being a constant int.

Assuming the function signature is the declaration/prototype:

Code: [Select]

void Shoot(bullet* Bullets[]);

[RulerOfNothing]

Well, I think there is no reason why that shouldn't work, but I have never had a clear picture of the minutae of C++'s type system (I usually try to keep away from such dark corners). I'm not too sure if I can provide any assisstance unfortunately.

[Simmura McCrea]

The exact error it gives is

no matching function for call to 'player::Shoot(bullet*&)'
candidates are: void player::Shoot(bullet**)

[Siquo]

And you're simply calling it as shoot(Bullets), not shoot(&Bullets) or something?
Hmmz.

This is one of the reasons I never use arrays

[kaijyuu]

I don't believe you can pass normal arrays through function calls like that.


Remember, arrays are just pointers. They are nothing more than that. They point to a block in memory and using the array brackets just offsets the address. If you want to pass an array, I'd suggest passing a vector or somesuch instead.


EDIT: In fact I'd suggest stop using arrays entirely and switch to vectors or something in the boost library. Their pointer nature adds a hell of a lot of overhead in specific situations that you do not want to deal with.

[Stargrasper]

Stargrasper = null;

I wish it were that simple in practice.  You know very well how things like to screw up if you so much as look at it funny.  At least when it segfaults, valgrind will give decent errors, unlike g++.

I don't believe you can pass normal arrays through function calls like that.


Remember, arrays are just pointers. They are nothing more than that. They point to a block in memory and using the array brackets just offsets the address. If you want to pass an array, I'd suggest passing a vector or somesuch instead.


EDIT: In fact I'd suggest stop using arrays entirely and switch to vectors or something in the boost library. Their pointer nature adds a hell of a lot of overhead in specific situations that you do not want to deal with.

I disagree with you, arrays are a lot more efficient if you happen to know how much stuff is going to be in them.  There's nothing stopping you from passing arrays as parameters to functions.  It's mildly annoying, but easily done if that's what you want to accomplish.

[kaijyuu]

I actually do use arrays with large blocks of data like bitmaps and graphics textures, but for normal use I avoid them like the plague.


One problem I nearly spent a week on was using arrays for object variables. I had these objects in a vector, and whenever it resized, the arrays lost protection and were randomly overwritten. Segfaults that happen at indeterminate times suck.

[MorleyDev]

Yeah, never use a vector if the address of the stored data matters. You'd have to use a list for that. Or write your own "arraylist" structure that creates blocks of members at a time. It's not that tricky, but the performance suffers compared to a vector since Random access still requires traversing a list.

It's not like you need to worry about shrinking on a pop, in most implementations and most situations a standard type will not shrink. Not in Java, not in C# and not in C++. Some consider it a bug, others a feature.

And if you need a fixed size array, ladies, gentleman: std::array.

[Sowelu]

The exact error it gives is

no matching function for call to 'player::Shoot(bullet*&)'
candidates are: void player::Shoot(bullet**)

I may be able to help.  How are you calling it?