std::equal_range
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Defined in header <algorithm>
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template< class ForwardIt, class T > std::pair<ForwardIt,ForwardIt> |
(1) | |
template< class ForwardIt, class T, class Compare > std::pair<ForwardIt,ForwardIt> |
(2) | |
value
[first, last)
包含的所有元素。范围是指由两个迭代器指向的第一个元素是“不低于”比value
和其他指标的第一个元素,一个“更大的,比value
”。可能可以得到第一个迭代器与lower_bound()
,第二 - upper_bound()
.value
in the sorted range [first, last)
. The range is defined by two iterators, one pointing to the first element that is not less than value
and another pointing to the first element greater than value
. The first iterator may be alternatively obtained with lower_bound()
, the second - with upper_bound()
.You can help to correct and verify the translation. Click here for instructions.
comp
.comp
.You can help to correct and verify the translation. Click here for instructions.
目录 |
[编辑] 参数
first, last | - | 检查的元素
Original: the range of elements to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
value | - | 值进行比较的元素
Original: value to compare the elements to The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
comp | - | comparison function which returns true if the first argument is less than the second. The signature of the comparison function should be equivalent to the following: bool cmp(const Type1 &a, const Type2 &b); The signature does not need to have const &, but the function must not modify the objects passed to it. |
Type requirements | ||
-ForwardIt must meet the requirements of ForwardIterator .
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[编辑] 返回值
value
和第二指向的第一个元素的第一“更大的”比value
. value
and the second pointing to the first element greater than value
. You can help to correct and verify the translation. Click here for instructions.
value
,last
返回的第一个元素。同样,如果没有任何元素“更大的”比value
,last
返回的第二个元素value
, last
is returned as the first element. Similarly if there are no elements greater than value
, last
is returned as the second elementYou can help to correct and verify the translation. Click here for instructions.
[编辑] 复杂性
first
和last
之间的距离在对数first
and last
You can help to correct and verify the translation. Click here for instructions.
[编辑] 可能的实现
First version |
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template<class ForwardIt, class T std::pair<ForwardIt,ForwardIt> equal_range(ForwardIt first, ForwardIt last, const T& value) { return std::make_pair(std::lower_bound(first, last, value), std::upper_bound(first, last, value)); } |
Second version |
template<class ForwardIt, class T, class Compare> std::pair<ForwardIt,ForwardIt> equal_range(ForwardIt first, ForwardIt last, const T& value, Compare comp); { return std::make_pair(std::lower_bound(first, last, value, comp), std::upper_bound(first, last, value, comp)); } |
[编辑] 为例
#include <algorithm> #include <vector> #include <iostream> struct S { int number; char name; S ( int number, char name ) : number ( number ), name ( name ) {} // only the number is relevant with this comparison bool operator< ( const S& s ) const { return number < s.number; } }; int main() { std::vector<S> vec = { {1,'A'}, {2,'B'}, {2,'C'}, {2,'D'}, {3,'F'}, {4,'G'} }; S value ( 2, '?' ); auto p = std::equal_range(vec.begin(),vec.end(),value); for ( auto i = p.first; i != p.second; ++i ) std::cout << i->name << ' '; }
Output:
B C D
[编辑] 另请参阅
返回一个迭代器的第一个元素“不低于”大于给定值 Original: returns an iterator to the first element not less than the given value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (函数模板) | |
返回一个迭代器的第一个元素“更大的”超过一定值 Original: returns an iterator to the first element greater than a certain value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (函数模板) | |
确定一个元素是否存在在一定的范围内 Original: determines if an element exists in a certain range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (函数模板) |