派生类调用基类方法时会自动转成基类类型

class A
{
    public:
    int a;
    void showthis()
    {
        printf("from A,this:%p\n", this);
    }
};
class B
{
    public:
    int b;
    void infothis()
    {
        printf("from B,this:%p\n", this);
    }
};
class C:public A, public B
{
    public:
    C(){
        printf("from C:this:%p\n", this);    
    }
};

int main()
{
    C c;
    c.showthis();
    c.infothis();
    
    return 0;
}