std::min_element
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<td><algorithm>
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<td >ForwardIt min_element( ForwardIt first, ForwardIt last );
<td > (1) </td> <td class="t-dcl-nopad"> </td> </tr> <tr class="t-dcl ">
<td >ForwardIt min_element( ForwardIt first, ForwardIt last,
<td > (2) </td> <td class="t-dcl-nopad"> </td> </tr> Template:ddcl list end
Finds the smallest element in the range [first, last)
. The first version uses operator< to compare the values, the second version uses the given comparison function comp
.
Contents |
Parameters
first, last | - | forward iterators defining the range to examine |
cmp | - | comparison function object (i.e. an object that satisfies the requirements of Compare) which returns true if if *a is less than *b .The signature of the comparison function should be equivalent to the following: bool cmp(const Type1& a, const Type2& b); While the signature does not need to have const&, the function must not modify the objects passed to it and must be able to accept all values of type (possibly const) |
Return value
Iterator to the smallest element in the range [first, last)
. If several elements in the range are equivalent to the smallest element, returns the iterator to the first such element. Returns last
if the range is empty.
Complexity
Exactly max(N-1,0) comparisons, where N = std::distance(first, last).
Possible implementation
First version |
---|
template<class ForwardIt> ForwardIt min_element(ForwardIt first, ForwardIt last) { if (first == last) return last; ForwardIt smallest = first; ++first; for (; first != last; ++first) { if (*first < *smallest) { smallest = first; } } return smallest; } |
Second version |
template<class ForwardIt, class Compare> ForwardIt min_element(ForwardIt first, ForwardIt last, Compare comp) { if (first == last) return last; ForwardIt smallest = first; ++first; for (; first != last; ++first) { if (comp(*first, *smallest)) { smallest = first; } } return largest; } |
Example
#include <algorithm> #include <iostream> #include <vector> int main() { std::vector<int> v{3, 1, 4, 1, 5, 9}; std::vector<int>::iterator result = std::min_element(v.begin(), v.end()); std::cout << "min element at: " << std::distance(v.begin(), result); }
Output:
min element at: 1