C++

參考

<algorithm>

function template
<algorithm>

std::min_element

預設 (1)
template <class ForwardIterator>  ForwardIterator min_element (ForwardIterator first, ForwardIterator last);
自定義 (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.

此函式模板的行為等同於
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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;
}

引數

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
二元函式，接受範圍中的兩個元素作為引數，並返回一個可轉換為 bool 的值。返回的值指示第一個引數傳遞的元素是否被視為小於第二個引數。
該函式不得修改其任何引數。
This can either be a function pointer or a function object.

返回值

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

示例

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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;
}

輸出
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


複雜度

Linear in one less than the number of elements compared.

資料競爭

訪問範圍 [first,last) 中的物件。

異常

如果任何比較操作丟擲異常，則該函式丟擲異常。
請注意，無效引數會導致未定義行為。

另見

max_element
返回範圍中的最大元素 （函式模板）
lower_bound
返回指向下界的迭代器 （函式模板）
min
返回最小值 （函式模板）