enumclassfruit{orange, apple};structS{usingenumfruit;// OK:引入 orange 与 apple 到 S 中};voidf(){S s;s.orange;// OK:指名 fruit::orangeS::orange;// OK:指名 fruit::orange} 引入两个同名的枚举项的两个usingenum声明会冲突。 enumclassfruit{orange, apple};enumclasscolor{red, orange};voi...
enum class color { red, orange, yellow }; struct highlight { using enum color; }; (C++20 起)局部类类声明可以在函数体内出现,此时它定义局部类。这种类的名字只存在于函数作用域中,且无法在函数外访问。 局部类的成员只能在该类的定义中声明,除了嵌套类成员也可以在该类的最近外围块作用域中声明。
When an unscoped enumeration is a class member, its enumerators may be accessed using class member access operators.and->: structX{enumdirection{left='l', right='r'};};X x;X*p=&x;inta=X::direction::left;// allowed only in C++11 and laterintb=X::left;intc=x.left;intd=p->left...
cppreference.com Create account Page Discussion Standard revision:DiffC++98/03C++11C++14C++17C++20C++23C++26 View Edit History std::errc C++ Utilities library Diagnostics library std::errc Defined in header<system_error> enumclasserrc; (since C++11) ...
【参考文献: https://en.cppreference.com/w/cpp/language/union 】 1//c++2//g++ -std=c++20 -O2 -Wall -pedantic -pthread main.cpp && ./a.out34#include <iostream>5#include <string>67union u_S8{9u_S()10{11std::cout <<"\n[os]#\tunion::S()"<<std::endl;12}1314u_S(std::...
关键字class允许你创建新的数据类型.class-name就是你要创建的类的名字,并且inheritance-list是一个对你创建的新类可供选择的定义体的表单.类的默认为私有类型成员,除非这个表单标注在公有或保护类型之下.object-list是一个或一组声明对象.举个例子: var-list是可选的. 例如: ...
问Cpp:如何解决此错误：“未定义的引用”(关于枚举)EN关于HTTP错误 404.17 - Not Found问题的解决方法...
intmain() {union{inta;constchar*p; }; a=1; p="Jennifer"; } union-like class #include<iostream>//S has one non-static data member (tag), three enumerator members,//and three variant members (c, n, d)structS {enum{CHAR, INT, DOUBLE} tag;union{charc;intn;doubled; ...
Reference-counted smart pointer. Use when you want to assign one raw pointer to multiple owners, for example, when you return a copy of a pointer from a container but want to keep the original. The raw pointer is not deleted until all shared_ptr owners have gone out of scope or have ...
Represents a reference type (e.g. int&). This API was introduced in Visual Studio 14 Update 2 (DkmApiVersion.VS14Update2).C++ Copy public ref class DkmNativeCppReferenceType : Microsoft::VisualStudio::Debugger::Native::Cpp::DkmNativeCppType...