$str = 'a';
echo ++$str; // prints 'b'
$str = 'z';
echo ++$str; // prints 'aa'
Its very useful to get next column name in an excel file.
But if I use similar code using -- operator to get the previous letter then its not working:
$str = 'b';
echo --$str; // prints 'b' but I need 'a'
$str = 'aa';
echo --$str; // prints 'aa' but I need 'z'
What can be the solution to get the previous letter similarly? And what can be the reason as its not working?