Question

以下代码：

enum Type {Prince, Princess, King, Queen, NumTypes};
enum Country {England, Belgium, Netherlands, NumCountries};

class Factory {
    static const std::array<std::array<int, NumTypes>, NumCountries> probabilities;
    static std::array<std::array<int, NumTypes>, NumCountries> initializeProbabilities() {
        std::array<std::array<int, NumTypes>, NumCountries> p;
        p[England] =     {29, 60, 80, 100};
        p[Belgium] =     {31, 66, 81, 100};
        p[Netherlands] = {25, 45, 90, 100};
      return p;
    }
};
const std::array<std::array<int, NumTypes>, NumCountries> Factory::probabilities = initializeProbabilities();

如果我改变了enum Country中元素的顺序，那么

是安全的，但是对于枚举类型元素的任何重新排序都不安全。如果不逐一初始化所有12个元素，避免这个问题的最佳方法是什么？

Answer 1

为了避免依赖订单，你应该写一些类似的东西：

p[England][Prince]=29;
p[England][Princess]=60;
p[England][King]=80;
p[England][Queen]=100;

p[Belgium][Prince]=31;
p[Belgium][Princess]=66;
p[Belgium][King]=81;
p[Belgium][Queen]=100;

Answer 2

这是Brian建议的解决方案（我认为这就是他的意思）。这可能是解决所述问题的最佳方法吗？

enum Type {Prince, Princess, King, Queen, NumTypes};
enum Country {England, Belgium, Netherlands, NumCountries};

class Factory {
    static const std::array<std::map<Type, int>, NumCountries> probabilities;
    static std::array<std::map<Type, int>, NumCountries> initializeProbabilities() {
        std::array<std::map<Type, int>, NumCountries> p;
        p[England] =     { {Prince, 29}, {Princess, 60}, {King, 80}, {Queen, 100} };
        p[Belgium] =     { {Prince, 31}, {Princess, 66}, {King, 81}, {Queen, 100} };
        p[Netherlands] = { {Prince, 25}, {Princess, 45}, {King, 90}, {Queen, 100} };
        return p;   
    }
};
const std::array<std::map<Type, int>, NumCountries> Factory::probabilities = initializeProbabilities();

或许他的意思是地图的地图。

初始化静态2D数组

2 个答案: