by Robert Sample » Sat Dec 19, 2015 7:10 am
DISPLAY is actually a VERY powerful tool. It allows you to show values (even COMP or COMP-3) on your output. Another simple, but effective, thing to do with DISPLAY is to put
immediately after each paragraph name to give you a trace facility. By selectively using them (make column 7 an asterisk for the ones you're not interested in at the time), you can zero in on a particular part of the program to look at. You can also use it to display the input buffer after reading a record so you know precisely what the input data is, or display the output buffer just before writing a record to verify things got updated correctly.
Yes, tools like Xpediter and STROBE are good debugging tools -- but since each of them can easily run more than $100,000 US dollars to buy and $20,000 US dollars per year to maintain, not every site has them available. Knowing how to use DISPLAY effectively is an important tool because there is no incremental cost (other than programmer time and a little CPU time) to use it, and DISPLAY can be used at every site (even those that have no other debugging tools available).
DISPLAY is actually a VERY powerful tool. It allows you to show values (even COMP or COMP-3) on your output. Another simple, but effective, thing to do with DISPLAY is to put [code]DISPLAY 'paragraph name'[/code] immediately after each paragraph name to give you a trace facility. By selectively using them (make column 7 an asterisk for the ones you're not interested in at the time), you can zero in on a particular part of the program to look at. You can also use it to display the input buffer after reading a record so you know precisely what the input data is, or display the output buffer just before writing a record to verify things got updated correctly.
Yes, tools like Xpediter and STROBE are good debugging tools -- but since each of them can easily run more than $100,000 US dollars to buy and $20,000 US dollars per year to maintain, not every site has them available. Knowing how to use DISPLAY effectively is an important tool because there is no incremental cost (other than programmer time and a little CPU time) to use it, and DISPLAY can be used at every site (even those that have no other debugging tools available).