• C

int c(const void *a,const void *b)
{
	int x = *(const int *)a;
	int y = *(const int *)b;

	if (x < y) return -1;
	if (x > y) return +1;
	return 0;
}

int main(void)
{
	int arr[]={1,6,3,7,2};
	qsort(arr,sizeof(arr)/sizeof(*arr),sizeof(*arr),c);

	return 0;
}

• Elixir

Enum.sort(items, c)

• Ada

type Integer_Comparator is not null access function (Left, Right : Integer) return Boolean;
      
package Integer_Vectors is new Vectors (Positive, Integer);
use Integer_Vectors;
      
procedure Sort_Using_Comparator (V : in out Vector; C : Integer_Comparator) is
   package Vector_Sorting is new Generic_Sorting (C.all);
   use Vector_Sorting;
         
begin
   Sort (V);
end Sort_Using_Comparator;

• Clojure

(sort c items)

• C++

std::ranges::sort(items, c);

• C++

struct is_less {
    bool operator () (int a, int b){
        return a < b;
    }
};

int main(){
    std::vector<int> items = {1337, 666, -666, 0, 0, 666, -666};
    std::sort(items.begin(), items.end(), is_less());

    std::vector<int> expected = {-666, -666, 0, 0, 666, 666, 1337};
    assert(items.size() == expected.size());
    for (size_t i = 0; i < items.size(); i++){
        assert(items[i] == expected[i]);
    }
    return 0;
}

• C#

Array.Sort(items, c);

• C#

items.Sort(c);

• C#

var orderdEnumerable = x.OrderBy(y => y, c);

• D

items.sort!c;

• Dart

items.sort(c);

• Erlang

lists:sort(C, List).

• Go

sort.Slice(items, func(i, j int) bool {
	return c(items[i], items[j])
})

• Go

type ItemsSorter struct {
	items []Item
	c     func(x, y Item) bool
}

func (s ItemsSorter) Len() int           { return len(s.items) }
func (s ItemsSorter) Less(i, j int) bool { return s.c(s.items[i], s.items[j]) }
func (s ItemsSorter) Swap(i, j int)      { s.items[i], s.items[j] = s.items[j], s.items[i] }

func sortItems(items []Item, c func(x, y Item) bool) {
	sorter := ItemsSorter{
		items,
		c,
	}
	sort.Sort(sorter)
}

• Go

slices.SortFunc(items, c)

• Go

type ItemCSorter []Item
func (s ItemCSorter) Len() int           { return len(s) }
func (s ItemCSorter) Less(i, j int) bool { return c(s[i], s[j]) }
func (s ItemCSorter) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }

func sortItems(items []Item) {
	sorter := ItemCSorter(items)
	sort.Sort(sorter)
}

• Haskell

result = sortBy c items

• JS

items.sort(c);

• Java

Arrays.sort(items, c);

• Java

Collections.sort(items, c);

• Kotlin

items.sortWith(c)

• Lisp

(sort items #'c)

• Lua

table.sort(items,c)

• Obj-C

[items sortUsingComparator:c];

• PHP

uasort($items, $c);

• Pascal

with TList.Create do try
  Sort(c);
finally
  Free;
end;

• Perl

sub c {
 $a <=> $b;
}

my @result = sort c @items;

• Python

items.sort(key=functools.cmp_to_key(c))

• Python

items.sort(key=c)

• Ruby

items.sort!{|a,b| a-b }

• Ruby

items.sort!(&c)

• Rust

items.sort_by(c);

• Scala

val c: Ordering[Int] = Ordering.Int
val sortedItems = items.sorted(c)

// Or using implicits:

val sortedItems = items.sorted

• Smalltalk

| c |
c := [ :a :b | a size <= b size ].  " example c for strings "
#('a' 'aaa' 'a' 'aaaa') asSortedCollection: c.
" => SortedCollection('a' 'a' 'aaa' 'aaaa') "