#include <algorithm>

Ran partial_sort_copy (In first, In last, Ran result_first, Ran result_last) 
Ran partial_sort_copy (In first, In last, Ran result_first, Ran result_last, Binary comp) 
Ran partial_sort_copy (Exec pol, In first, In last, Ran result_first, Ran result_last) 
Ran partial_sort_copy (Exec pol, In first, In last, Ran result_first, Ran result_last, Binary comp) 
 
[last,res] = partial_sort_copy (Range1 r1, Range2 result, Binary comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {}) 
[last,res] = partial_sort_copy (In first, In last, Ran result_first, Ran result_last, Binary comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {})

Kopiert die kleinsten Elemente des Bereiches [first,last) aufsteigend geordnet in den Bereich [result_first,result_last).

Rückgabewert: result_first+N bzw. {last,result_first+N} als Struktur mit Elementen namens in, out mit N = min(last-first, result_last-result_first).

partial_sort().

partial_sort_copy.cpp

#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
 
struct Person
{
  std::string name;
  int born;
  int died;
};
 
struct Person2
{
  std::string name;
  int age;
 
  Person2(Person p = {})
  : name(p.name)
  , age(p.died-p.born)
  {
  }
};
 
int main()
{
  auto persons = std::vector<Person> 
  {
    { "Galilei", 1564, 1642 },
    { "Newton" , 1642, 1726 },
    { "Hawking", 1942, 2018 },
  };
 
  for (auto [name, born, died] : persons)
  {
    std::cout << name << '\t' << born << '-' << died  << '\n';
  }
  std::cout << "-----------------\n";
 
  auto persons2 = std::vector<Person2>(2);
 
  std::ranges::partial_sort_copy(persons, persons2, {}, &Person::name, &Person2::name);	
 
  for (auto [name, age] : persons2)
  {
    std::cout << name << '\t' << age  << '\n';
  }
}
 
/*
Galilei 1564-1642
Newton  1642-1726
Hawking 1942-2018
-----------------
Galilei 78
Hawking 76
*/