初始化std :: vector< unsigned int>带有连续无符号整数的列表 [英] Initialization of std::vector<unsigned int> with a list of consecutive unsigned integers

问题描述

我想使用一种特殊的方法来初始化 std :: vector< unsigned int> ，在我用作参考的C ++书中对此进行了描述（德语书Ulrich Breymann的 Der C ++程序员，以防万一。该书中有一个有关STL序列类型的部分，特别是指 list ， vector 和 deque 。在本节中，他写道，有两种特殊的此类序列类型的构造函数，即，如果 X 引用这种类型，则

I want to use a special method to initialize a std::vector<unsigned int> which is described in a C++ book I use as a reference (the German book 'Der C++ Programmer' by Ulrich Breymann, in case that matters). In that book is a section on sequence types of the STL, referring in particular to list, vector and deque. In this section he writes that there are two special constructors of such sequence types, namely, if Xrefers to such a type,

X(n, t) // creates a sequence with n copies of t
X(i, j) // creates a sequence from the elements of the interval [i, j)

我想使用第二个间隔 unsigned int ，即

I want to use the second one for an interval of unsigned int, that is

std::vector<unsigned int> l(1U, 10U);

以获得以 {1,2，...， 9} 。但是，我得到的是一个向量，该向量具有一个 unsigned int 的值10：-|第二种变体是否存在，如果是，那么如何强制调用它？

to get a list initialized with {1,2,...,9}. What I get, however, is a vector with one unsigned int with value 10 :-| Does the second variant exist, and if yes, how do I force that it is called?

推荐答案

重新阅读此处描述的段落每个参数是什么。具体来说，应该提到 i 和 j 不是值，而是迭代器。此构造函数非常常用于复制其他类型的容器。如果要获取值序列，则 Boost库提供了计数迭代器，它正是您想要的。

Reread the paragraphs near there describing what each of the parameters are. Specifically, it should mention that i and j are not values, but iterators. This constructor is very commonly used to make copies of other types of containers. If you want to get a sequence of values, the Boost library provides a counting iterator, that does exactly what you want.

std::vector<unsigned int> numbers(
     boost::counting_iterator<unsigned int>(0U),
     boost::counting_iterator<unsigned int>(10U));

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