前置声明(Forward Declaration)是C++中的一种技术,用于在声明某个实体(通常是类、函数、变量等)的名称而无需提供其详细定义。前置声明的目的是为了告诉编译器某个实体的存在,以便在稍后的代码中引用它,而不必在声明的地方提供完整的定义。这可以提高编译速度和减少编译依赖性。 前置声明是C/C++开发中比较常用的技巧,...
52 C:\Dev-Cpp\Projektyyy\strategy\Tiles.h invalid use of undefined type `struct tile_tree_apple' 46 C:\Dev-Cpp\Projektyyy\strategy\Tiles.h forward declaration of `struct tile_tree_apple' some part of my code: class tile_tree_apple; class tile_tree : public tile { public: tile onDe...
classMan :publicPerson { public: Man(void); ~Man(void); private: Person child; }; ///Man.h/// #pragmaonce //#include "person.h" //去掉 classPerson;//加入 classMan:publicPerson { public: Man(void); ~Man(void); private: Person child; }; error C2504: “Person” : 未定义基类 ...
classMan :publicPerson { public: Man(void); ~Man(void); private: Person child; }; ///Man.h/// #pragmaonce //#include "person.h" //去掉 classPerson;//加入 classMan:publicPerson { public: Man(void); ~Man(void); private: Person child; }; error C2504: “Person” : 未定义基类 ...
class B:A { ... A member; } 结果,编译就会出错,说找不到类形A。解决的办法是在B.h里#include “A.h”。但是有时候不用#include “A.h”,只要在classB:A前加class A;就可以了。更严重的是不但要#include “A.h”,还要class A;。 起初...
Forward class declaration // myheader.h #ifndef MYHEADER_H_ _ #define MYHEADER_H_ _ class A; // No need to include A's header class B { public: void f(const A& a); // ... private: A* a_; }; #endif Somewhere else there is a header and perhaps an implementation file that...
1classX;//This is a forward declaration 1//声明一个非完整类型的成员指针或者引用(reference)2classFoo {3X *p;4X &r;5}67//声明一个以非完整类型为参数,或者返回非完整类型的函数8voidf1(X);9X f2();1011//定义以非完整类型为参数或者返回非完整类型指针,引用的函数 (但是不能用它的成员)12voidf3...
If you declare an attribute of type MaybeThatOtherWay, not a reference nor a pointer, the compiler must know the full definition of the class to determine the size of the outer class. Thus, you can't use forward declaration and that kind of field declaration, whether it's a nested class...
While searching through this group , people suggested using forward declarations and typedefs for templates as // in myfile.h template<typename T,typename R> class some_class; C / C++ 11 8353 Forward declaration of static variable by: Jef Driesen | last post by: I have the ...
for class message is a forward declarationfor class message is a forward declaration for class message is a forward declaration:因为课堂信息是一个前向声明©2022 Baidu |由 百度智能云 提供计算服务 | 使用百度前必读 | 文库协议 | 网站地图 | 百度营销 ...