function template
<algorithm>

std::sort

默认 (1)
template <class RandomAccessIterator>  void sort (RandomAccessIterator first, RandomAccessIterator last);
自定义 (2)
template <class RandomAccessIterator, class Compare>  void sort (RandomAccessIterator first, RandomAccessIterator last, Compare comp);
Sort elements in range
Sorts the elements in the range [first,last) into ascending order.

元素使用第一个版本的 operator< 进行比较,第二个版本使用 comp 进行比较。

Equivalent elements are not guaranteed to keep their original relative order (see stable_sort).

参数

first, last
Random-access iterators to the initial and final positions of the sequence to be sorted. 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.
RandomAccessIterator shall point to a type for which swap is properly defined and which is both move-constructible and move-assignable.
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 to go before the second in the specific strict weak ordering it defines.
该函数不得修改其任何参数。
This can either be a function pointer or a function object.

返回值



示例

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// sort algorithm example
#include <iostream>     // std::cout
#include <algorithm>    // std::sort
#include <vector>       // std::vector

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

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

int main () {
  int myints[] = {32,71,12,45,26,80,53,33};
  std::vector<int> myvector (myints, myints+8);               // 32 71 12 45 26 80 53 33

  // using default comparison (operator <):
  std::sort (myvector.begin(), myvector.begin()+4);           //(12 32 45 71)26 80 53 33

  // using function as comp
  std::sort (myvector.begin()+4, myvector.end(), myfunction); // 12 32 45 71(26 33 53 80)

  // using object as comp
  std::sort (myvector.begin(), myvector.end(), myobject);     //(12 26 32 33 45 53 71 80)

  // print out content:
  std::cout << "myvector contains:";
  for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)
    std::cout << ' ' << *it;
  std::cout << '\n';

  return 0;
}

输出
myvector contains: 12 26 32 33 45 53 71 80


复杂度

On average, linearithmic in the distance between first and last: Performs approximately N*log2(N) (where N is this distance) comparisons of elements, and up to that many element swaps (or moves).

数据竞争

范围[first,last)内的对象将被修改。

异常

如果任何元素比较、元素交换(或移动)或迭代器操作抛出异常,则会抛出异常。
请注意,无效参数会导致未定义行为

另见