std::max_element
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| Defined in header <algorithm>
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| template< class ForwardIt > ForwardIt max_element( ForwardIt first, ForwardIt last ); |
(1) | |
| template< class ForwardIt, class Compare > ForwardIt max_element( ForwardIt first, ForwardIt last, Compare comp ); |
(2) | |
Finds the greatest element in the range [first, last). The first version uses operator< to compare the values, the second version uses the given comparison function comp.
目录 |
[编辑] 参数
| first, last | - | 前向迭代器定义的范围检查
Original: forward iterators defining the range to examine The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. | |||||||||
| cmp | - | comparison function which returns true if if *a is less than *b. The signature of the comparison function should be equivalent to the following:
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
Iterator to the greatest element in the range [first, last). If several elements in the range are equivalent to the greatest element, returns the iterator to the first such element. Returns last if the range is empty.
[编辑] 复杂性
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[编辑] 可能的实现
| First version |
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template<class ForwardIt> ForwardIt max_element(ForwardIt first, ForwardIt last) { if (first == last) { return last; } ForwardIt largest = first; ++first; for (; first != last; ++first) { if (*largest < *first) { largest = first; } } return largest; } |
| Second version |
template<class ForwardIt, class Compare> ForwardIt max_element(ForwardIt first, ForwardIt last, Compare comp) { if (first == last) { return last; } ForwardIt largest = first; ++first; for (; first != last; ++first) { if (comp(*largest, *first)) { largest = first; } } return largest; } |
[编辑] 为例
#include <algorithm> #include <iostream> #include <vector> #include <cmath> static bool abs_compare(int a, int b) { return (std::abs(a) < std::abs(b)); } int main() { std::vector<int> v{ 3, 1, -14, 1, 5, 9 }; std::vector<int>::iterator result; result = std::max_element(v.begin(), v.end()); std::cout << "max element at: " << std::distance(v.begin(), result) << '\n'; result = std::max_element(v.begin(), v.end(), abs_compare); std::cout << "max element (absolute) at: " << std::distance(v.begin(), result); }
Output:
max element at: 5 max element (absolute) at: 2
[编辑] 另请参阅
| 返回的范围内的最小元素 Original: returns the smallest element in a 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） | |
| （C++11） |
返回的最小和最大的元素在一定范围内 Original: returns the smallest and the largest element in a 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） |
| 返回较大的两个元素 Original: returns the larger of two elements 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） | |
