char x;

   x = 12;

   Storage allocated for x: 1 byte (8 bits)

   Binary          Decimal            Hexadecimal
   00001100        12                 0C

Binary represenatation uses 2 symbols: 0, 1

Decimal representation uses 10 symbols: 0 to 9

Hexadecimal uses 16 symbols: 0 to 9 plus A to F