There are two formats for decimal numbers:

1. Zoned Decimal
2. Packed Decimal

Zoned Decimal Numbers

-  Generally used for input/output

-  Represent one decimal digit per byte

-  Each byte of is made up of two hex digits

      left  ->  zone digit       right ->  numeric digit

- The numeric digit is the number represented by the byte

- The zone digit of all but the RIGHTMOST byte must be F

- The zone digit of the rightmost byte is used to indicate the sign
  of the number
  
     A, C, E, or F    positive number
     B or D           negative number
     
     F1F2F3F4   zoned decimal representation of +1234

     F1F2F3B4   zoned decimal representation of -1234

- Can be generated on a DC statement by using a storage class of Z

     - the initial value can contain a sign or a decimal point
   
     - if the sign is omitted, assumed to be positive
     
     - if plus sign is specified, rightmost zone digit is C
     
     - if negative sign is specified, rightmost zone digit is D
     
     - if a decimal point is specified, treated as an implied
       decimal point

   DC   2Z'-1'         D1D1
   DC   Z'+2'          C2
   DC   Z'2'           C2
   DC   ZL3'4'         F0F0C4
   DC   2ZL2'-9'       F0D9F0D9
   DC   Z'1.10'        F1F1C0

- Maximum zoned decimal number can have 16 digits

-  Used for arithmetic

-  Each byte, except for the rightmost, represents two decimal digits

-  The rightmost byte contains a decimal digit and the sign digit

      left  ->  numeric digit      right ->  sign digit

-  The sign digit is used to indicate the sign of the number
  
     A, C, E, or F    positive number
     B or D           negative number
     
-  To represent a number:

     1. Move the sign to the right (end) of the number
     2. If there is an even number of digits, add a zero on the left
     3. Change the sign to an appropriate sign digit
     
   To represent -1234:
     
     1. 1234-
     2. 01234-
     3. 01 23 4D
     
- Can be generated on a DC statement by using a storage class of P

     - the initial value can contain a sign or a decimal point
 
     - if the sign is omitted, assumed to be positive
     
     - if plus sign is specified, rightmost sign digit is C
     
     - if negative sign is specified, rightmost sign digit is D
     
     - if a decimal point is specified, treated as an implied
       decimal point

   DC   2P'-1'         1D1D
   DC   P'+2'          2C
   DC   P'2'           2C
   DC   PL3'4'         00004C
   DC   2PL2'-9'       009D009D
   DC   P'1.10'        110C

- Maximum packed decimal number can have 31 digits