Subtract 1 without arithmetic operators | PHP code to subtract one from a given number ; Flip all the set bits until we find a 1 ; flip the rightmost 1 bit ; Driver Code
< ? php function subtractOne ( $ x ) { $ m = 1 ; while ( ! ( $ x & $ m ) ) { $ x = $ x ^ $ m ; $ m <<= 1 ; } $ x = $ x ^ $ m ; return $ x ; } echo subtractOne ( 13 ) ; ? >