当我试着运行它时,它说: 错误C2065:“默认”:未声明的标识符 “守则”: #include "stdafx.h" #include <iostream> #include <string> using namespace std; struct A { int age; A(int x): age(x){}; A() = default; }; int _tmain(int argc, _TCHAR* argv[]) { A t 浏览3提问于2012-...