C++ 概念： DefaultConstructible

 

C++

语言

概念

实用工具库

字符串库

集装箱库

算法库

迭代器库

Numerics库

输入/输出库

本地化库

正则表达式库 （C++11）

原子操作库 （C++11）

线程的支持库 （C++11）

 

C++ 的概念

基础
DefaultConstructible CopyAssignable CopyConstructible	MoveAssignable （C++11） MoveConstructible （C++11） Destructible
库
EqualityComparable LessThanComparable Swappable （C++11） ValueSwappable （C++11）	NullablePointer （C++11） Hash （C++11） Allocator
容器
Container SequenceContainer ReversibleContainer	AssociativeContainer AllocatorAwareContainer UnorderedAssociativeContainer （C++11）
容器元素
CopyInsertable （C++11） MoveInsertable （C++11）	EmplaceConstructible （C++11）
迭代器
Iterator OutputIterator InputIterator	ForwardIterator BidirectionalIterator RandomAccessIterator
随机数
SeedSequence （C++11） RandomNumberEngine （C++11）	RandomNumberDistribution （C++11） UniformRandomNumberGenerator （C++11） RandomNumberEngineAdaptor （C++11）
并发
BasicLockable （C++11） Lockable （C++11） TimedLockable （C++11）	Mutex （C++11） TimedMutex （C++11）
其它
CharTraits pos_type off_type Clock （C++11）	UnaryTypeTrait （C++11） BinaryTypeTrait （C++11） TransformationTrait （C++11） TrivialClock （C++11）

 

指定该类型的一个实例是默认构造.

Original:

Specifies that an instance of the type can be default constructed.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

要求

该类型必须实现以下功能：1

Original:

The type must implement the following functions:

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Type::Type

Type::Type();

默认构造函数: constructs an instance of a type with default contents.

The following expressions must have the specified effects:

表达 Original: Expression The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.	Effects
Type a1;	a1默认初始化. Original: a1 is default-initialized. The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Type a2{};	a2的值初始化. Original: a2 is value-initialized. The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Type{} Type()	一个临时对象类型Type值初始化. Original: a temporary object of type Type is value-initialized. The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

另请参阅

is_default_constructible is_trivially_default_constructible is_nothrow_default_constructible （C++11） （C++11） （C++11）	检查如果一个类型有一个默认的构造函数 Original: checks if a type has a default constructor The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （类模板）