~                        Bitwise NOT operator (unary)

 ~exp                    bitwise NOT
  exp                    any integral type (int, char, enum, etc)

    The  unary  operator  ~  performs  a  bit-by-bit  complement  on   exp,
    converting each 0 bit to  a 1 and each 1  bit to a 0. The  result is of
    the  same  type  as  exp.    For  string  expressions,  the  bit-by-bit
    complement is performed on each  character of the string.   For numeric
    expressions, the  result of  the expression  is first  converted to  an
    integer value and the complement operation performed.  For example:

           j = 3953;            # j == 0x0F71 = 0000111101110001 (base 2)
           i = ~j;              # i == 0xF08E = 1111000010001110 (base 2)