Does PHP include toupper and tolower functions? [closed]

Answer 1

strtolower() and strtoupper()

Answer 2

strtoupper() and strtolower().

Answer 3

echo strtolower('TEXT'); //text
echo strtoupper('text'); //TEXT
echo ucwords('text text'); //Text Text
echo ucfirst('text text'); //Text text
echo lcfirst('TEXT TEXT'); //tEXT TEXT

Answer 4

echo strtolower('HELLO');
echo strtoupper('hello');