INITIALIZE Statement

INITIALIZE sets the variables with system-defined initial values based on their data types. It's functionally equivalent to one or more MOVE statements. It is a convenient way to reset the full copybook, and group variable, ensuring that they start with predictable values.

Syntax -

INITIALIZE group-variable-1 [group-variable-2 ...]
    [REPLACING ALPHABETIC | 
	           ALPHANUMERIC | 
			   ALPHANUMERIC-EDITED | 
			   NUMERIC | 
			   NUMERIC-EDITED
					DATA BY {literal-1} ALL {literal-2}]

Note! All statements coded in [ ] are optional.

Parameters -

group-variable-1, group-variable-2, ...- The variable names we wish to initialize.
REPLACING - Optional. It is used to replace default initializing values with new ones.
- NUMERIC DATA - Specifies that numeric variable initalized with literal-1 value instead of ZEROES. Similarly, ALPHABETIC DATA, ALPHANUMERIC DATA, ...
- BY literal-1 - Specifies the new literal-1 value to initialize the variables.
- ALL literal-2 - Specifies the new literal-2 value to initialize non-numeric variables.

How INITIALIZE Works?

For NUMERIC fields (like PIC 9), they are set to zeros.
For ALPHANUMERIC fields (like PIC X), they are set to spaces.
For ALPHABETIC fields (like PIC A), they are set to spaces.
For ALPHA-NUMERIC EDITED and NUMERIC EDITED fields, they retain their specific edit symbols, and other positions are set to zeros or spaces as appropriate.
FILLER items, redefined items, and items with USAGE are not initialized by the INITIALIZE statement.

Practical Example -

Scenario - Initialize usage in COBOL program.

Code -

----+----1----+----2----+----3----+----4----+----5----+
       IDENTIFICATION DIVISION.
       PROGRAM-ID. INITGRP.
	   AUTHOR. MTH.

       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-VAR.
          05 WS-NAME        PIC X(20). 
          05 FILLER         PIC X(05). 
          05 WS-GENDER      PIC X(01). 
          05 FILLER         PIC X(05). 
          05 WS-TODAY       PIC 9(08). 
          05 FILLER         PIC X(01). 

       PROCEDURE DIVISION.

           MOVE ALL '-'         TO WS-VAR.
           DISPLAY 'BEFORE INIT:  ' WS-VAR.

           INITIALIZE WS-VAR.
           DISPLAY 'AFTER INIT:   ' WS-VAR.

           STOP RUN.

Output -

BEFORE INIT:  ----------------------------------------
AFTER INIT:                       ----- -----00000000-

Explaining Example -

FILLER positions are not initalized with INITIALIZE statement and remaining variables initialized according to their data type.