基类訪问权限 类继承方式 子类訪问权限  
       
public   public  
protected public protected  
private   No Access  
public   protected  
protected protected protected  
private   No Access  
public   private  
protected private private  
private   No Access  
       
       
       
基类訪问权限 类继承方式 子类訪问 子类对象訪问
       
public   ok ok
protected public ok no
private   no no
public   ok ok
protected protected ok no
private   no no
public   ok no
protected private ok no
private   no no