function template
<algorithm>

std::min_element

default (1)
template <class ForwardIterator>
  ForwardIterator min_element (ForwardIterator first, ForwardIterator last);
custom (2)
template <class ForwardIterator, class Compare>
  ForwardIterator min_element (ForwardIterator first, ForwardIterator last,
                               Compare comp);
Return smallest element in range
Returns an iterator pointing to the element with the smallest value in the range [first,last).

The comparisons are performed using either operator< for the first version, or comp for the second; An element is the smallest if no other element compares less than it. If more than one element fulfills this condition, the iterator returned points to the first of such elements.

The behavior of this function template is equivalent to:
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template <class ForwardIterator>
  ForwardIterator min_element ( ForwardIterator first, ForwardIterator last )
{
  if (first==last) return last;
  ForwardIterator smallest = first;

  while (++first!=last)
    if (*first<*smallest)    // or: if (comp(*first,*smallest)) for version (2)
      smallest=first;
  return smallest;
}


Parameters

first, last
Input iterators to the initial and final positions of the sequence to compare. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
comp
Binary function that accepts two elements in the range as arguments, and returns a value convertible to bool. The value returned indicates whether the element passed as first argument is considered less than the second.
The function shall not modify any of its arguments.
This can either be a function pointer or a function object.

Return value

An iterator to smallest value in the range, or last if the range is empty.

Example

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// min_element/max_element example
#include <iostream>     // std::cout
#include <algorithm>    // std::min_element, std::max_element

bool myfn(int i, int j) { return i<j; }

struct myclass {
  bool operator() (int i,int j) { return i<j; }
} myobj;

int main () {
  int myints[] = {3,7,2,5,6,4,9};

  // using default comparison:
  std::cout << "The smallest element is " << *std::min_element(myints,myints+7) << '\n';
  std::cout << "The largest element is "  << *std::max_element(myints,myints+7) << '\n';

  // using function myfn as comp:
  std::cout << "The smallest element is " << *std::min_element(myints,myints+7,myfn) << '\n';
  std::cout << "The largest element is "  << *std::max_element(myints,myints+7,myfn) << '\n';

  // using object myobj as comp:
  std::cout << "The smallest element is " << *std::min_element(myints,myints+7,myobj) << '\n';
  std::cout << "The largest element is "  << *std::max_element(myints,myints+7,myobj) << '\n';

  return 0;
}


Output:
The smallest element is 2
The largest element is 9
The smallest element is 2
The largest element is 9
The smallest element is 2
The largest element is 9

Complexity

Linear in one less than the number of elements compared.

Data races

The objects in the range [first,last) are accessed.

Exceptions

Throws if any comparison throws.
Note that invalid arguments cause undefined behavior.

See also

max_element
Return largest element in range (function template )
lower_bound
Return iterator to lower bound (function template )
min
Return the smallest (function template )

C++