std::min_element

 

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Defined in header <algorithm>
template< class ForwardIterator > ForwardIterator min_element( ForwardIterator first, ForwardIterator last );	(1)
template< class ForwardIterator, class Compare > ForwardIterator min_element( ForwardIterator first, ForwardIterator last,                              Compare comp );	(2)

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.

Parameters

first, last	-	forward iterators defining the range to examine
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: 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. The types  Type1 and  Type2 must be such that an object of type ForwardIterator can be dereferenced and then implicitly converted to both of them. ​

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 ForwardIterator> ForwardIterator min_element(ForwardIterator first, ForwardIterator last) { if (first == last) return last;   ForwardIterator smallest = first; ++first; for (; first != last; ++first) { if (*first < *smallest) { smallest = first; } } return smallest; }
Second version
template<class ForwardIterator, class Compare> ForwardIterator min_element(ForwardIterator first, ForwardIterator last, Compare comp) { if (first == last) return last;   ForwardIterator 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

See also

max_element	returns the largest element in a range (function template)
minmax_element (C++11)	returns the smallest and the largest element in a range (function template)
min	returns the smaller of two elements (function template)