Hi ,
When would you advise to use COMP and COMP-3 variables? In today's world what are the advantage of these variables have over PIC X() Usage DISPLAY variables when memory is not a problem?
Interviewer has already mentioned about memory and that was the answer I wanted to say; now what can be the advanatage ?
When would you advise to use COMP and COMP-3 variables?
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Re: When would you advise to use COMP and COMP-3 variables?
Memory was never, or rarely, a problem which would lead to the use of binary or packed-decimals. Disk space more so, but not really.
The benefits of binary and packed-decimal were, and remain, performance. A USAGE DISPLAY (the default if no usage specified) field has to be converted if arithmetic is carried out with it, then converted back if a result is to be stored there.
Also, when using a field for subscripting, USAGE DISPLAY will be converted to binary.
So, to avoid the conversions, you define the field as how it will be used.
The benefits of binary and packed-decimal were, and remain, performance. A USAGE DISPLAY (the default if no usage specified) field has to be converted if arithmetic is carried out with it, then converted back if a result is to be stored there.
Also, when using a field for subscripting, USAGE DISPLAY will be converted to binary.
So, to avoid the conversions, you define the field as how it will be used.
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