• PHP

for ($i=0;$i<mb_strlen($s);$i++) {
    $characters[] = mb_substr($s, $i, 1, 'UTF-8');
}

$characters = array_reverse($characters);
$t = implode($characters);

• C

char *strrev(char *s)
{
	size_t len = strlen(s);
	char *rev = malloc(len + 1);

	if (rev) {
		char *p_s = s + len - 1;
		char *p_r = rev;

		for (; len > 0; len--)
			*p_r++ = *p_s--;
		*p_r = '\0';
	}
	return rev;
}

• Clojure

(def t (str/reverse s))

• Clojure

(let [s "hello"
      t (apply str (reverse s))]
  t)

• Cobol

IDENTIFICATION DIVISION.
PROGRAM-ID. reverse string.
PROCEDURE DIVISION.
    MOVE FUNCTION REVERSE(s) TO t
STOP RUN.

• C++

auto t = ::std::ranges::reverse(s);

• C#

string t = string.Create(s.Length, s, static (span, s) =>
{
    s.AsSpan().CopyTo(span);
    span.Reverse();
});

• C#

char[] charArray = s.ToCharArray();
Array.Reverse(charArray);
string t = new string(charArray);

• D

auto t = s.retro.array;

• Dart

var t = s.split('').reversed.join();

• Dart

var t = new String.fromCharCodes(s.runes.toList().reversed);

• Elixir

t = String.reverse(s)

• Erlang

T = lists:reverse(S)

• Fortran

  character(len=:), allocatable :: t
  integer :: i, n

  allocate (t, mold=s)
  n = len(s)
  do i = 0, n - 1
     t(n-i : n-i) = s(i+1 : i+1)
  end do

• Go

runes := []rune(s)
for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
   runes[i], runes[j] = runes[j], runes[i]
}
t := string(runes)

• Go

runes := []rune(s)
slices.Reverse(runes)
t := string(runes)

• Go

func reverse(s string) string {
	if len(s) <= 1 {
		return s
	}
	var b strings.Builder
	b.Grow(len(s))
	for len(s) > 0 {
		r, l := utf8.DecodeLastRuneInString(s)
		s = s[:len(s)-l]
		b.WriteRune(r)
	}
	return b.String()
}

• Haskell

t = reverse s :: String

• JS

var t = s.split("").reverse().join("");

• Java

char a[] = s.toCharArray(), c;
int i, m = a.length, n = m-- / 2, z;
for (i = 0; i < n; ++i) {
    c = a[i];
    a[i] = a[z = m - i];
    a[z] = c;
}
String t = new String(a);

• Java

String t = new StringBuilder(s).reverse().toString();

• Java

String t = "";
for (char c : s.toCharArray())
    t = c + t;

• Java

String t = s.chars()
    .mapToObj(x -> valueOf((char) x))
    .reduce((a, b) -> b + a)
    .get();

• Kotlin

val t = s.reversed()

• Lisp

(reverse s)

• Lua

function utf8.reverse(s)
	local r = ""
	for p,c in utf8.codes(s) do
		r = utf8.char(c)..r
	end
	return r
end

t = utf8.reverse(s)

• Obj-C

NSMutableString *t=[NSMutableString string];
[s enumerateSubstringsInRange:NSMakeRange(0,s.length)
  options:NSStringEnumerationReverse|NSStringEnumerationByComposedCharacterSequences
  usingBlock:^(NSString *part, NSRange r1, NSRange r2, BOOL *stop) {
    [t appendString:part];
}];

• Pascal

function reverse(const str: string): string;
var
  i, j: Integer;
begin
  j := length(str);
  setlength(reverse, j);
  for i := 1 to j do
    reverse[i] := str[j - i + 1];
end;

• Pascal

Function ReverseString(const AText: string): string;
var
    i,j:longint;
begin
  setlength(result,length(atext));
  i:=1; j:=length(atext);
  while (i<=j) do
    begin
      result[i]:=atext[j-i+1];
      inc(i);
    end;
end;

• Perl

my $s = 'cafe' . "\N{COMBINING ACUTE ACCENT}";
my $t = join '', reverse $s =~ /\X/g;

• Python

t = s[::-1]

• Python

t = ''.join(reversed(s))

• Ruby

t = s.reverse

• Rust

let t: String = s.chars().rev().collect();

• Rust

let t = s.chars().rev().collect::<String>();

• Scala

s.reverse

• Scheme

(define t (list->string (reverse (string->list s))))

• Smalltalk

t := s reversed.

• VB

Dim string_t = StrReverse(string_s)