STL array的crbegin方法(7)

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原文地址:http://www.cplusplus.com/reference/array/array/crbegin/
public member function
<array>

std::array::crbegin

const_iterator crbegin() const noexcept;
Return const_reverse_iterator to reverse beginning
Returns a const_reverse_iterator pointing to the last element in the array container.

返回一个const_reverse_iterator指向array容器的最后一个元素。

例子:

#include <iostream>#include <array>using namespace std;int main(){array<int,5> ai={1,2,3,4,5};cout<<"ai is ";for(int i:ai)cout<<i<<" ";cout<<"*ai.crbegin()="<<*ai.crbegin()<<endl;}
运行截图:




const_reverse_iterator is an iterator that points to const content and iterates in reverse order. This iterator can be increased and decreased (unless it is itself also const), just like the iterator returned by array::rbegin, but it cannot be used to modify the contents it points to.

一个const_reverse_iterator是一个逆序的指向常量的迭代器。这个迭代器可以被递增或者递减(除非该迭代器自己是const的),返回的迭代器和rbegin的是很相似的,但是不能用于修改其指向的内容。


Parameters

none

Return Value

const_reverse_iterator to the beginning of the sequence.
返回一个反转的指向序列开头的迭代器。

Member type const_reverse_iterator is a reverse random access iterator type that points to a const element (see array member types).

迭代器的类型属于随机访问迭代其。


Example

12345678910111213141516
// array::crbegin/crend#include <iostream>#include <array>int main (){  std::array<int,6> myarray = {10, 20, 30, 40, 50, 60} ;  std::cout << "myarray backwards:";  for ( auto rit=myarray.crbegin() ; rit < myarray.crend(); ++rit )    std::cout << ' ' << *rit;   // cannot modify *rit  std::cout << '\n';  return 0;}
Edit & Run


Output:
myarray backwards: 60 50 40 30 20 10

Complexity

Constant.

Iterator validity

No changes.

Data races

No contained elements are accessed by the call, but the iterator returned can be used to access them. Concurrently accessing or modifying different elements is safe.
容器的所有元素都不会被访问,但是返回的迭代器可以用来访问他们,同时访问以及修改不同的元素是安全的。

Exception safety

No-throw guarantee: this member function never throws exceptions.

The copy construction or assignment of the returned iterator is also guaranteed to never throw.

该成员方法不会抛出异常。

通过复制或者赋值获得的该迭代器的副本也不会抛出异常。


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author:天下无双

Email:coderguang@gmail.com

2014-8-27

于GDUT

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