棋子层次结构设计：继承与类型字段 [英] Chess piece hierarchy design: inheritance vs type fields

问题描述

我有件的基类

 class piece;

和包含派生对象的数组

piece* board[8][8];

通过虚拟功能实现优势，简洁设计。缺点，如果我必须在板上找到一块或比较一件我必须恢复到动态铸造（或typeid）。它是丑陋的，并且在制作数百万个请求时可能会很糟糕。

Advantage, clean design through virtual functions. Disadvantage, if I have to find a piece in the board or compare a piece I have to revert to dynamic casting (or typeid). It’s ugly and could be a performance hog when making millions of requests.

另一方面，如果我创建一个单件类的数组，那么它有一个类型字段为了识别件，我没有这个问题（它应该更快）但我必须制作超级丑陋的switch语句。我想，由于件数是有限的，我不认为自己制造了那么多开关，这可能最终是一个更好的选择，你觉得怎么样？

In the other hand, if I make an array of a single piece class, that has a type field for identifying pieces, I don’t have this problem (and it should be faster) but I have to make super ugly switch statements. I guess that since the number of pieces is finite and I don’t see myself making that many of switches, this could be in the end a better choice, what do you think?

这是为了好玩（所以没有位线）。

This is for fun (so no bitboard).

编辑1

阅读一些答案，我认为仅使用类型字段进行运算符重载（==，！= ...）可以带来两个单词中最好的。

Reading some answers, I think using type fields only for operator overloading (==,!=...) could bring the best of both words.

提升:: variant看起来也很有趣。

The boost::variant looks very interesting too.

推荐答案

我会选择类层次结构。

为了找到一件作品，你可以为每件作品保留一份单独的清单。所以你知道在哪里寻找每一种类型。

For finding a piece you can keep a separeted list for each piece type. So you know where to look for each piece type.

为了比较你也可以依赖虚拟方法。

For comparison you can rely on virtual methods too.

另一个方法是使用组件架构（如下所述： http：// cowboyprogramming.com/2007/01/05/evolve-your-heirachy/ ），但我认为这对于国际象棋游戏来说太过分了，你可以清楚地知道这些类型并知道这些类型不会很快改变:) 。

Another aproach is to use a component architecture (like described here: http://cowboyprogramming.com/2007/01/05/evolve-your-heirachy/), but I think it is too much for a chess game where you clealy know the types and know that those types will not change soon :).

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