Palindrome Golf

Answer 1

24 characters in Perl.

sub p{$_[0]eq+reverse@_}

Answer 2

Another python version that is rather shorter (21 chars):

R=lambda s:s==s[::-1]

Answer 3

Haskell, 28 chars, needs Control.Arrow imported.

p=uncurry(==).(id&&&reverse)

Answer 4

Inspired by previous post, 69 characters

p(char*a){char*b=a,q=0;while(*++b);while(*a)q|=*a++!=*--b;return!q;}

EDIT: Down one char:

p(char*a){char*b=a,q=0;while(*++b);while(*a)q|=*a++%*--b;return!q;}

EDIT2: 65 chars:

p(char*a){char*b=a;while(*b)b++;while(*a&&*a++==*--b);return!*a;}

Answer 5

PHP:

function p($s){return $s==strrev($s);} // 38 chars

or, just

$s==strrev($s); // 15 chars

Answer 6

52 characters in C, with the caveat that up to half the string will be overwritten:

p(char*s){return!*s||!(s[strlen(s)-1]-=*s)&&p(++s);}

Without library calls it's 64 characters:

p(char*s){char*e=s;while(*e)++e;return!*s||!(*--e-=*s)&&p(++s);}