There are only 3 programs

Software
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In another place:

My reply there was complaining about sloppy or lazy programmers, however it did remind me of something a lecturer said many years back while I was at uni;

There are only 3 programs:

  1. The Input and Validate
  2. The Update
  3. The Report

And while this was really aimed at COBOL programming at the time (very early 80s), I do wonder just how true that still is today in other languages and systems and that maybe we’ve forgotten?

Sensors → (MQTT) Database → Display

Hours worked → Update Payroll → Print Cheque

I get the feeling that the validate is missing a lot of times - a recent example I noticed was viewing vehicles on ebay - Mileage: NaN. What does that tell you? The Input wasn’t validated or the Display wasn’t checked for an invalid (or more likely missing in this case) value? (And what’s the side-effect of a missing value when updating the database?) And similarly we read about utility companies sending bills for 100x the expected amount, or a much worse example might be the Horizon/Post Office scandal:

where at least one person died through suicide as a result.

Sloppy/Lazy programming? You decide…

-Gordon

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My personal impression is that input validation is the least loved part of programming (possibly including documentation). However, it is probably the most important one, since, as the display/report enjoys all the care and love, what are you actually displaying?
And, as exemplified by the BPO scandal, there are real consequences.

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  1. the test program. Does it work like you expect? Do you run out memory?
    Is the algorithm correct? Did somebody break something outside your program.
    Did some idiot install a different OS version or DLL.
    Ben.
    PS I am composing dummy email and use the spell checker there, and then paste
    here.