STL deque的方法cbegin(7)

原文地址：http://www.cplusplus.com/reference/deque/deque/cbegin/

public member function

<deque>

std::deque::cbegin

const_iterator cbegin() const noexcept;

Return const_iterator to beginning

Returns aconst_iteratorpointing to the first element in the container.

返回一个const_iterator指向容器的第一个元素。

Aconst_iteratoris an iterator that points to const content. This iterator can be increased and decreased (unless it is itself also const), just like theiteratorreturned bydeque::begin, but it cannot be used to modify the contents it points to, even if thedequeobject is not itself const.

const_iterator可以递增以及递减，但是不可以用来修改元素。

If the container isempty, the returned iterator value shall not be dereferenced.

例子：

#include <iostream>
#include <deque>
#include <vector>
using namespace std;
int main()
{
	deque<int> di{1,2,3,4,5};
	for(int i:di)
		cout<<i<<" ";
	cout<<endl;
	cout<<"di.cbegin()="<<*di.cbegin()<<endl;
	
	deque<double> dd;
	cout<<"dd.cbegin()="<<*dd.cbegin()<<endl;
	


}

运行截图：

Parameters

none

Return Value

Aconst_iteratorto the beginning of the sequence.

返回一个const_iterator指向序列的开头。

Member typeconst_iteratoris arandom access iteratortype that points to a const element.

Example

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

// deque::cbegin/cend #include <iostream> #include <deque> int main () { std::deque<int> mydeque = {10,20,30,40,50}; std::cout << "mydeque contains:"; for (auto it = mydeque.cbegin(); it != mydeque.cend(); ++it) std::cout << ' ' << *it; std::cout << '\n'; return 0; }

Edit & Run

Output:

mydeque contains: 10 20 30 40 50

Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed.
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.

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.

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//今后的翻译将以简洁为主，只翻译其主要意思，一些重复率太高的也将不再翻译，不懂的可以留言，不再每句翻译。

转载请注明出处：http://blog.csdn.net/qq844352155
author:天下无双

Email:[e-mail]

2014-9-1

于GDUT

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