Static Members:

Static Members:

c++中一些静态成员函数的有趣的事实

静态成员函数没有this指针

class Test{
private:
public:
static Test *fun() {
return *this;//compiler error
}
};

静态成员函数不能是虚函数

成员函数名相同且参数相同，如果其中一个是静态成员函数，那么他们就不能重载

class Test{
private:
public:
static void fun();
void fun();
};

静态成员函数不能被声明为const，const volatile，volatile

class Test{
private:
public:
static void fun() const{return;}
};

C++中静态成员

1

class A{
private:
public:
A() { cout << "A's constructer is called" << endl; }
};

class B{
private:
static A a;
public:
B() { cout << "B's constructer is called" << endl; }
};

int main() {
B b;

return 0;
}

这里仅仅调用B的构造函数，原因是静态成员变量必须在类声明中被声明，而不是定义。他们还必须在类外用范围解析符(::)定义

如果尝试不定义就使用静态成员变量，编译出错

如下：

2

class A{
private:
int x;
public:
A() { cout << "A's constructer is called" << endl; }
};

class B{
private:
static A a;
public:
B() { cout << "B's constructer is called" << endl; }
static A getA() { return a; }
};

int main() {
B b;
A a = b.getA();
return 0;
}

编译出错

3

class A{
private:
int x;
public:
A() { cout << "A's constructed is called " << endl; }
};

class B{
private:
static A a;
public:
B() { cout << "B's constructed is called " << endl; }
static A getA() { return a; }
};

A B::a;

int main() {
B b1,b2,b3;
A a = b1.getA();
return 0;
}

注意，这里B调用三次，而A调用一次，这是因为a是静态成员变量，为所有对象共享；另外静态成员变量可以不需对象即可访问。

补充，其实静态成员在main函数之前就已经被调用了，即在定义静态对象的时候，其已经生成。

class A{
private:

public:
A() { cout << "a's constructor called" << endl; }
};

class B{
private:
static A a;
public:
B() { cout << "b's constructor called" << endl; }
static A getA() { return a; }
};

A B::a;

int main() {
return 0;
}

输出



4

class A{
private:
int x;
public:
A() { cout << "A's constructed is called " << endl; }
};

class B{
private:
static A a;
public:
B() { cout << "B's constructed is called " << endl; }
static A getA() { return a; }
};

A B::a;

int main() {
A a = B::getA();
return 0;
}