类别继承程序代码再用

int main()
{
  Derived A_Derived;
  cout<<"Accessing Derived&＃39;s data members"
     <<"inherited form Base..."<  cout<<"Derived::pub_att&＃61;"<  &＃xff0f;&＃xff0f;cout<<"Derived::pro_att&＃61;"<  cout<  cout<<"Call Derived&＃39;s members funcitons"<<"inherited form Base.."<  A_Derived.pub_show();
  &＃xff0f;&＃xff0f;A_Derived.pro_show();
  &＃xff0f;&＃xff0f;A_Derived.pri_show();
  A_Derived.call_show();
  A_Derived.show();
return 0;
}

[root&＃64;localhost code]# g&＃43;&＃43; public_inh.cpp
public_inh.cpp:19: function body for constructor missing
public_inh.cpp:19: invalid data member initialization
public_inh.cpp:19: (use &＃96;&＃61;&＃39; to initialize static data members)
public_inh.cpp:19: ISO C&＃43;&＃43; forbids declaration of &＃96;pro_att&＃39; with no type
public_inh.cpp:19: ISO C&＃43;&＃43; forbids declaration of &＃96;pub_att&＃39; with no type
public_inh.cpp:19: syntax error before &＃96;{&＃39; token
public_inh.cpp:19: missing &＃39;;&＃39; before right brace
public_inh.cpp:20: semicolon missing after declaration of &＃96;Base&＃39;
public_inh.cpp: In constructor &＃96;Base::Base()&＃39;:
public_inh.cpp:19: parse error before &＃96;int&＃39;
public_inh.cpp: At global scope:
public_inh.cpp:20: extraneous &＃96;int&＃39; ignored
public_inh.cpp:20: conflicting types for &＃96;Base pub_att&＃39;
public_inh.cpp:19: previous declaration as &＃96;int pub_att&＃39;
public_inh.cpp:25: parse error before &＃96;}&＃39; token
public_inh.cpp:29: parse error before &＃96;void&＃39;
public_inh.cpp:30: missing &＃39;;&＃39; before right brace
public_inh.cpp:38: syntax error before &＃96;::&＃39; token
public_inh.cpp:41: syntax error before &＃96;<<&＃39; token
public_inh.cpp:42: syntax error before &＃96;<<&＃39; token
public_inh.cpp:43: syntax error before &＃96;<<&＃39; token
public_inh.cpp:44: syntax error before &＃96;<<&＃39; token
public_inh.cpp: In function &＃96;int main()&＃39;:
public_inh.cpp:53: &＃96;class Derived&＃39; has no member named &＃96;pub_att&＃39;
public_inh.cpp:58: no matching function for call to &＃96;Derived::pub_show()&＃39;
public_inh.cpp:14: &＃96;void Base::pro_show()&＃39; is protected
public_inh.cpp:59: within this context
public_inh.cpp:8: &＃96;void Base::pri_show()&＃39; is private
public_inh.cpp:60: within this context
public_inh.cpp:61: no matching function for call to &＃96;Derived::call_show()&＃39;
public_inh.cpp:62: no matching function for call to &＃96;Derived::show()&＃39;

根据以上报错&＃xff0c;

一一分析排查&＃xff1a;

:pri_att(1),pro_att(2),pub_att(3){}

主要还是大部分在细节上&＃xff0c;非技术性错误&＃xff0e;

经过修改在编译&＃xff1a;

public_inh.cpp: In constructor &＃96;Base::Base()&＃39;:
public_inh.cpp:19: class &＃96;Base&＃39; does not have any field named &＃96;pro_att&＃39;
public_inh.cpp: In member function &＃96;void Derived::show()&＃39;:
public_inh.cpp:43: &＃96;pro_att&＃39; undeclared (first use this function)
public_inh.cpp:43: (Each undeclared identifier is reported only once for each
   function it appears in.)
public_inh.cpp:6: &＃96;int Base::pri_att&＃39; is private
public_inh.cpp:44: within this context
public_inh.cpp: In function &＃96;int main()&＃39;:
public_inh.cpp:54: &＃96;class Derived&＃39; has no member named &＃96;pro_att&＃39;
public_inh.cpp:14: &＃96;void Base::pro_show()&＃39; is protected
public_inh.cpp:59: within this context
public_inh.cpp:8: &＃96;void Base::pri_show()&＃39; is private
public_inh.cpp:60: within this context
public_inh.cpp:61: no matching function for call to &＃96;Derived::call_show()&＃39;

再修改&＃xff0c;编译&＃xff1a;

[root&＃64;localhost code]#  g&＃43;&＃43; public_inh.cpp
public_inh.cpp: In member function &＃96;void Derived::show()&＃39;:
public_inh.cpp:6: &＃96;int Base::pri_att&＃39; is private
public_inh.cpp:44: within this context
public_inh.cpp: In function &＃96;int main()&＃39;:
public_inh.cpp:12: &＃96;int Base::pro_att&＃39; is protected
public_inh.cpp:54: within this context
public_inh.cpp:14: &＃96;void Base::pro_show()&＃39; is protected
public_inh.cpp:59: within this context
public_inh.cpp:8: &＃96;void Base::pri_show()&＃39; is private
public_inh.cpp:60: within this context

这就很好证实了在&＃xff50;&＃xff55;&＃xff42;&＃xff4c;&＃xff49;&＃xff43;继承中&＃xff50;&＃xff52;&＃xff49;&＃xff3f;&＃xff41;&＃xff54;&＃xff54;的不可见性

再次编译

出错情况&＃xff1a;

[root&＃64;localhost code]# g&＃43;&＃43; public_inh.cpp
public_inh.cpp: In function &＃96;int main()&＃39;:
public_inh.cpp:12: &＃96;int Base::pro_att&＃39; is protected
public_inh.cpp:54: within this context

[root&＃64;localhost code]# g&＃43;&＃43; public_inh.cpp
[root&＃64;localhost code]# g&＃43;&＃43; -o public_inh.cpp public_inh.out
g&＃43;&＃43;: public_inh.out: No such file or directory
g&＃43;&＃43;: no input files

但是&＃xff1a;

[root&＃64;localhost code]# g&＃43;&＃43;  public_inh.cpp -o public_inh.out 成功编译
[root&＃64;localhost code]#

结果如下&＃xff1a;

[root&＃64;localhost code]# g&＃43;&＃43;  public_inh.cpp -o public_inh.out
[root&＃64;localhost code]# ./public_inh.out
Accessing Derived&＃39;s data membersinherited form Base...
Derived::pub_att&＃61;3
Call Derived&＃39;s members funcitonsinherited form Base..
Base::pub_show() is called !
Derived ::call_fun is called
Base::pub_show() is called !
Base::pro_show() is called!
Derived ::show() is called!
Base::pub_att&＃61;3
Base::pro_att&＃61;2

本程序测试的特点&＃xff1a;

代码&＃xff1a;

#include
#include
using namespace std;
class library_object
{
  protected:
    char name[30];
    long index;
  public:
    void set_data(const char *i_name)
     {
       strcpy(name,i_name);
       index &＃61;1;
      }
};
class Book :public library_object
{
  private:
  bool on_shelf;
  public :
  void show_data()
{
  cout<<"name:"<

  cout<<"index:"<  if(on_shelf&＃61;&＃61;true)
     cout<<"on shelf"<  else
     cout<<"not on shelf "<}
};
class Reader :public library_object
{
  public :
   void show_data()
    {
     cout<<"name:"<     cout<<"index:"<    }
};
int main()
{
  Reader A_Reader ;
  Book  A_Book;
  A_Reader.set_data("Jorn");
  A_Reader.show_data();
  A_Book.set_data("the C&＃43;&＃43; Bible");

A_Book.show-data();
return 0;
}

[root&＃64;localhost code]# g&＃43;&＃43; inheritance.cpp
inheritance.cpp: In function &＃96;int main()&＃39;:
inheritance.cpp:47: &＃96;class Book&＃39; has no member named &＃96;show&＃39;
inheritance.cpp:47: &＃96;data&＃39; undeclared (first use this function)
inheritance.cpp:47: (Each undeclared identifier is reported only once for each
   function it appears in.)

显然是一个小错&＃xff1a;

[root&＃64;localhost code]# g&＃43;&＃43; inheritance.cpp -o inheritance.out
[root&＃64;localhost code]# ./inheritance.out
name:Jornindex:1
name:the C&＃43;&＃43; Bibleindex:1not on shelf
[root&＃64;localhost code]#

程序分析&＃xff1a;

&＃xff50;&＃xff52;&＃xff41;&＃xff56;&＃xff49;&＃xff54;&＃xff45;继承代码&＃xff1b;

#include
using namespace std;
class Base
{
  private: int pri_att;
           void pri_show()
           { cout<<"Base::pri_show() is called!"<  protected: int pro_att;
              void pro_show()
           { cout<<"Base::pro_show() is called!"<   public : int pub_att;
              void pub_show()
           { cout<<"Base::pub_show() is called!"<           Base()
           :pri_att&＃61;1;pro_att&＃61;1;pub-att&＃61;3;
}
class Derived:private Base
{
public :
   void call_fun();
   void show();
};
void Derived ::call_fun()

{
cout<cout<cout<cout<cout<<"Derived ::call_fun is called!"<pub_show();
pro_show();
// pri_show();
}
void Derived::show()
{
  cout<cout<<"Derived ::show() is called "<  cout<  cout<  cout<<"Base::pub_att&＃61;"<  cout<<"Base::pro_att&＃61;"<//  cout<<"Base::pri_att&＃61;"<}
int main()
{
return 0;

&＃xff5d;

出错如下:

[root&＃64;localhost code]# g&＃43;&＃43; private_inh.cpp
private_inh.cpp:15: function body for constructor missing
private_inh.cpp:15: ISO C&＃43;&＃43; forbids declaration of &＃96;pro_att&＃39; with no type
private_inh.cpp:15: ISO C&＃43;&＃43; forbids initialization of member &＃96;pro_att&＃39;
private_inh.cpp:15: making &＃96;pro_att&＃39; static
private_inh.cpp:15: ISO C&＃43;&＃43; forbids in-class initialization of non-const static
   member &＃96;pro_att&＃39;
private_inh.cpp:15: declaration of &＃96;int Base::pro_att&＃39;
private_inh.cpp:8: conflicts with previous declaration &＃96;int Base::pro_att&＃39;
private_inh.cpp:15: syntax error before &＃96;-&＃39; token
private_inh.cpp:15: duplicate member &＃96;Base::pro_att&＃39;
private_inh.cpp:17: semicolon missing after declaration of &＃96;Base&＃39;
private_inh.cpp: In constructor &＃96;Base::Base()&＃39;:
private_inh.cpp:15: parse error before &＃96;:&＃39; token
private_inh.cpp: At global scope:
private_inh.cpp:22: multiple types in one declaration
private_inh.cpp: In member function &＃96;void Derived::show()&＃39;:
private_inh.cpp:38: parse error before &＃96;.&＃39; token
private_inh.cpp:39: parse error before &＃96;.&＃39; token
private_inh.cpp: At global scope:
private_inh.cpp:50: parse error before &＃96;}&＃39; token

修改之后;

[root&＃64;localhost code]# g&＃43;&＃43; private_inh.cpp
private_inh.cpp:17: semicolon missing after declaration of &＃96;Base&＃39;
private_inh.cpp:22: multiple types in one declaration
private_inh.cpp: In member function &＃96;void Derived::show()&＃39;:
private_inh.cpp:38: parse error before &＃96;.&＃39; token
private_inh.cpp:39: parse error before &＃96;.&＃39; token

编译出错&＃xff1a;

: &＃96;Second_Derived Second_Derived::call_fun()&＃39; and &＃96;void
   Second_Derived::call_fun()&＃39; cannot be overloaded
private_inh.cpp:53: semicolon missing after declaration of &＃96;class
   Second_Derived&＃39;
private_inh.cpp: In member function &＃96;void Second_Derived::show()&＃39;:
private_inh.cpp:69: parse error before &＃96;{&＃39; token
private_inh.cpp:74: &＃96;A_Dervied&＃39; undeclared (first use this function)
private_inh.cpp:74: (Each undeclared identifier is reported only once for each
   function it appears in.)
private_inh.cpp:81: &＃96;A_Derived&＃39; undeclared (first use this function)
private_inh.cpp:87: return-statement with a value, in function declared with a
   void return type
[root&＃64;localhost code]#