What is the difference between comp and comp-3 usage ?

Answer : COMP is 2 bytes.COMP-3 is 8 bytes…

Comp :

  • COMP is 2 bytes.
  • COMP is used for Binary Representation it allows only S and 9.
  • COMP stores the data in the binary format.
  • With COMP fields, you have to drag out a calculator and convert the hex value to find out the true value that is being used in a program.
  • Memory usage is,
      s9(5)-s9(9) – 4bytes
      s9(1)-s9(4) – 2bytes
      s9(10)-s9(18) – 8bytes


  • COMP-3 is 8 bytes.
  • Comp-3 is used for Packed Decimal values it allows S 9 V mostly it is useful for Decimal Calculation Values.
  • COMP-3 stores the data in the BCD(Binary Coded Decimal)format.
  • It is used to avoid rounding issues that occur when binary numbers are used to represent decimal fractions.
  • This is particularly vital in systems that method massive volumes of economic transactions/amounts
  • Memory usage is
      • n/2 + 1 (Even)
      n+1/2 (odd)

Example :

  • Banking, Credit cards, etc.

Other cobol usages :

  • The usage clause specifies how the data item being stored internally .If no usage clause specified , the default usage clause would Usage is display
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