[英]C++11: How to initialize array of pointers of some class with nullptr?
I am new to C++. 我是C ++的新手。 I have class named
MyDate
. 我有一个名为
MyDate
类。 In addition I have a class named Calendar
which has a member type of array of pointers to MyDate
objects. 另外,我有一个名为
Calendar
的类,该类具有指向MyDate
对象的指针数组的成员类型。 How should I declare and initialize members of the array to nullptr
in the constructor of Calendar
? 我应该如何在
Calendar
的构造函数中将数组的成员声明并初始化为nullptr
?
Personally, I'd probably do it like this: 就个人而言,我可能会这样做:
class Calendar {
/* Methods: */
Calendar() noexcept
{ for (auto & ptr: m_dates) ptr = nullptr; }
/* Fields: */
/* Array of 42 unique pointers to MyDate objects: */
std::array<MyDate *, 42> m_dates;
};
PS: You might want to consider using smart pointers like std::unique_ptr
or std::shared_ptr
instead of raw pointers. PS:您可能要考虑使用诸如
std::unique_ptr
或std::shared_ptr
类的智能指针,而不是原始指针。 Then you wouldn't need to explicitly initialize these in the Calendar
constructor at all: 然后,您根本不需要在
Calendar
构造函数中显式初始化它们:
class Calendar {
/* Fields: */
/* Array of 42 pointers to MyDate objects: */
std::array<std::unique_ptr<MyDate>, 42> m_dates;
};
EDIT: Without C++11 features, I'd do this: 编辑:没有C ++ 11功能,我会这样做:
class Calendar {
/* Methods: */
Calendar()
{ for (std::size_t i = 0u; i < 42u; ++i) m_dates[i] = NULL; }
/* Fields: */
/* Array of 42 unique pointers to MyDate objects: */
MyDate * m_dates[42];
};
Smart pointers default-initialize to nullptr
: 智能指针默认初始化为
nullptr
:
class Calendar
{
std::array<std::unique_ptr<Date>, 42> m_dates;
};
Otherwise, std::array
is an aggregate, so an empty braced init list will zero-initialize all scalar fields: 否则,
std::array
是一个聚合,因此空的初始化列表将对所有标量字段进行零初始化:
class Calendar
{
std::array<Date *, 42> m_dates {};
};
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.