WebIn C++, classes and structs can be forward-declared like this: classMyClass;structMyStruct; In C++, classes can be forward-declared if you only need to use the pointer-to-that-class type (since all object pointers are the same size, and this is what the compiler cares about). WebJul 5, 2012 · using namespace std; class A { public: void run () { B b ("hi"); b.run (this); } void print (string &msg) { cout << msg << endl; } private: class B { public: B (string m) : msg (m) {} void run (A *a) { a->print (msg); } private: string msg; }; }; int main () { A a; a.run (); return 0; } Share Follow

Forward declare pointers-to-structs in C++ - Stack Overflow

WebAug 31, 2024 · You can only forward declare an enum when the underlying type is explicitly specified. This is not allowed: enum A; enum A { X,Y}; // not allowed With gcc the error message is still a little misleading, stating that it would be disallowed to forward declare enums in general which isn't correct anymore ( … WebC++ 返回对正向声明类型（C+；+；）的引用,c++,visual-studio,forward-declaration,C++,Visual Studio,Forward Declaration,我有一个类方法，它返回对某个对 … bakers and baristas dc

c++ - Forward declarations of unnamed struct - Stack Overflow

WebDec 12, 2012 · You can declare default arguments for a template only for the first declaration of the template. If you want allow users to forward declare a class … WebApr 20, 2012 · Since you want to forward declare an anonymous struct, you can neither give it a name in the forward declaration of the original entity, nor can you refer to it when typedefing it. The "logical" syntax would be: struct ; typedef bar; class {}; WebMar 28, 2012 · Yes, using forward declarations is always better. Some of the advantages they provide are: Reduced compilation time. No namespace pollute. (In some cases)may … arban nargund