How to Check ‘Comp Variable’ for Spaces and Low-Values

In COBOL, the prime use of the comp variable is for faster calculation and to save memory. Here is a resolution on how to check for spaces or Low-values. It’s tricky but not complex. Remember as general notes while coding, if you have a Comp* variable, you need to check for proper initialization.

Comp Variable

COBOL Definition for Comp*

Here I use comp-4 to demonstrate.

01 COUNTERS.
    05 WS_COUNT    COMP-4.
    05 WS_COUNT_X  REDEFINES  WS_COUNT PIC X(02).           
01 MY_DATA       PIC 9(04).

I move the comp-4 value to MY_DATA, which is a numeric type. When the input WS_COUNT has valid numeric, you will not face any issue, but if the WS_COUNT has spaces or low-values, junk data populates to MY_DATA. Below is my example to avoid junk data. Useful for COBOL/Mainframe projects.

COBOL MOVE Statement

MOVE WS_COUNT  TO MY_DATA.

Resolution to Check for Spaces and Low-Values

IF WS_COUNT_X SPACES or LOW_VALUES
   MOVE ZEROS  TO MY_DATA
ELSE
   MOVE WS_COUNT TO MY_DATA
END-IF.

This way, you can avoid populating junk data in the target variable. It applies to all COMP* variables. Check out more on Comp-4, Comp-5 and Comp-6.

Important Points

  • Comp-4 internally takes 2 bytes, So I use 2 bytes in redefines
  • Comp-5 internally takes 4 bytes
  • Comp-6 internally takes 8 bytes

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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.