它们将共享相同的staticVar实例。 
 
 为了让每个派生类获得自己的静态变量，你需要使用不同的名称来声明另一个静态变量。 
 
 然后，您可以在基类中使用一对虚函数来获取和设置变量的值，并在每个派生类中覆盖该对，以获取并设置该类的“本地”静态变量。 或者，您可以使用返回引用的单个函数： 
 
class Base {
    static int staticVarInst;
public:
    virtual int &staticVar() { return staticVarInst; }
}
class Derived: public Base {
    static int derivedStaticVarInst;
public:
    virtual int &staticVar() { return derivedStaticVarInst; }
}
 
 然后，您可以使用： 
 
staticVar() = 5;
cout << staticVar();

They will each share the same instance of staticVar.
 
In order for each derived class to get their own static variable, you'll need to declare another static variable with a different name.
 
You could then use a virtual pair of functions in your base class to get and set the value of the variable, and override that pair in each of your derived classes to get and set the "local" static variable for that class. Alternatively you could use a single function that returns a reference:
 
class Base {
    static int staticVarInst;
public:
    virtual int &staticVar() { return staticVarInst; }
}
class Derived: public Base {
    static int derivedStaticVarInst;
public:
    virtual int &staticVar() { return derivedStaticVarInst; }
}
 
You would then use this as:
 
staticVar() = 5;
cout << staticVar();