[心得] 原來繼承不可逆

看板C_and_CPP作者gecer (gecer)時間8年前 (2017/10/01 10:51)推噓8(8推 0噓 20→)

留言28則, 4人參與討論串1/1

#include <iostream> using namespace std; class Base { public: virtual void function1() {cout<<"Base :: function1()\n";}; virtual ~Base(){}; }; class D1: public Base { public: ~D1(){}; void function1() { cout<<"D1 :: function1()\n";}; }; class D2: public D1 { public: ~D2(){}; void function1() { cout<<"D2 :: function1()\n";}; }; int main() { D2 *d2=new D2; D1 *d1=new D1; Base *b=new Base; D1 *dd; dd=d2; dd->function1(); dd=d1; dd->function1(); dd=b; dd->function1(); return (0); } 小弟先定義class Base->繼承給D1->繼承給D2 then 宣告D1 *dd 指標給各class 當dd指標Base(dd=b)時 compiler 便會出現 error: invalid conversion from 'Base*' to 'D1*' [-fpermissive 原來繼承不可指標逆回上一層 -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 111.255.30.171 ※ 文章網址: https://www.ptt.cc/bbs/C_and_CPP/M.1506826318.A.2B3.html ※ 編輯: gecer (111.255.30.171), 10/01/2017 10:52:49 ※ 編輯: gecer (111.255.30.171), 10/01/2017 10:54:27

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