#include <iostream>
using namespace std;

class Base{
public:
    static int val1;  //类内定义，类外初始化，如果直接初始化编译器会报错
    int val2;
private:
    static int val3;
};
int Base::val1(1);  //类外初始化，通过类名访问静态成员
int Base::val3(2);  //类外初始化，即便是私有属性也可以通过类名访问静态成员


int main()
{

    Base base1;
    Base base2;
    
    base1.val1 = 10;
    base2.val1 = 11;
    cout << sizeof(BasE) <<endl; //类的大小只有四字节，说明静态成员并不依赖类存在，有自己的独立空间 
    cout << base1.val1 << " " << base2.val1 << endl;   
    system("pause");
    return 0;
}

#include <iostream>
using namespace std;

class Base{
public:
    static int val1;  //类内定义，类外初始化，如果直接初始化编译器会报错
    int val2;
private:
    static int val3;
};
int Base::val1(1);  //类外初始化，通过类名访问静态成员
int Base::val3(2);  //类外初始化，即便是私有属性也可以通过类名访问静态成员

class Son : public Base {
public:
    static int val1; //类内定义，类外初始化,与父类同名的静态变量
};
int Son:: val1 = 3; //类外初始化

int main()
{

    Son son1;    
    cout << son1.val1 << " " << son1.base::val1 << endl;  //通过对象方式访问静态成员变量
    cout << Son::val1 << " " << Base::val1 << endl; //通过类名方式访问静态成员变量
    system("pause");
    return 0;
}

#include <iostream>
using namespace std;

class Base{
public:
    static int val1;
    int val2;
    
    static void func1(){
        //val2 = 10; //静态成员函数访问非静态成员变量，编译会报错
        val1 = 10; //只能访问静态成员
        cout << "func1()" << endl;
    }
private:
    static void func2(){
        cout << "func2()" << endl;
    }
};

int Base::val1(1);

int main()
{
    cout << "Base size = " << sizeof(BasE) << endl;
    Base base1;
    Base base2;

    base1.func1(); //通过对象访问
    //base1.func2(); //类的私有权限，不能访问
    Base::func1(); //通过对象访问
   // Base::func2(); //私有权限，不能访问
    
    cout << base1.val1 << " " << base2.val1 << endl;
    system("pause");
    return 0;
}