是否继承了静态字段？ [英] Are static fields inherited?

问题描述

当静态成员被继承时，它们对于整个层次结构是静态的，或者只是那个类，即：

When static members are inherited, are they static for the entire hierarchy, or just that class, i.e.:

class SomeClass
{
public:
    SomeClass(){total++;}
    static int total;
};

class SomeDerivedClass: public SomeClass
{
public:
    SomeDerivedClass(){total++;}
};

int main()
{
    SomeClass A;
    SomeClass B;
    SomeDerivedClass C;
    return 0;
}

在所有三个实例中总共为3， code> SomeClass 和1为 SomeDerivedClass ？

would total be 3 in all three instances, or would it be 2 for SomeClass and 1 for SomeDerivedClass?

推荐答案

3在所有情况下，因为 SomeDerivedClass 继承的 static int total SomeClass ，不是一个不同的变量。

3 in all cases, since the static int total inherited by SomeDerivedClass is exactly the one in SomeClass, not a distinct variable.

作为@ejames发现，并在他的回答中指出。

actually 4 in all cases, as @ejames spotted and pointed out in his answer, which see.

编辑：第二个问题的代码缺少 int 在这两种情况下，但添加它使它成功，即：

the code in the second question is missing the int in both cases, but adding it makes it OK, i.e.:

class A
{
public:
    static int MaxHP;
};
int A::MaxHP = 23;

class Cat: A
{
public:
    static const int MaxHP = 100;
};

适用于A :: MaxHP和Cat :: MaxHP的不同值子类是不继承基类的静态，因为，可以说，它是隐藏它与它自己同义的。

works fine and with different values for A::MaxHP and Cat::MaxHP -- in this case the subclass is "not inheriting" the static from the base class, since, so to speak, it's "hiding" it with its own homonymous one.

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