Why do so many "developers" not understand 'null'?
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
A guy on the team I just joined was somewhat miffed about the whole nullable feature in C#. He had learned in university that object oriented languages had nullable references. And C# is an object oriented language... so obviously we could not force references to have values.
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
Richard, this is a problem of perception, you seem to think anyone who posts in Q&A is a "developer". Most are probably just learning (and you are their teaching resource) and a lot of them are code monkeys at best.
Never underestimate the power of human stupidity - RAH I'm old. I know stuff - JSOP
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Well, after all it is the Billion Dollar Mistake[^], as Tony Hoare himself put it :-D Recently I had to go through a large code base where the authors went crazy using Non-nullable pointers[^] almost everywhere. What can I say, seems a complicated problem for many people :rolleyes:
Mircea
Mircea Neacsu wrote:
Tony Hoare himself put it
But I'm unsure if he doesn't really believe it himself; nulls are still a very good idea, but dangerous in the wrong hands. But so are chain saws, and hair spray, big deal.
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
trønderen has also said it well. Even the C language has confusion on this topic. Yes, I too believe that they have distinct meanings. Remember my posing the question of why is this a valid statement in C zero = 0; value = malloc( zero ); value is not null nor zero. Why would I want to allocate zero memory? Here is what ChatAI says In the C programming language, calling malloc(0) is allowed and returns a pointer to a memory block of size 0. This is specified in the C standard, which states that malloc(0) is equivalent to malloc(1). The reason for this behavior is that malloc is intended to allocate memory dynamically, and a request for 0 bytes of memory is considered a valid request. Allocating a block of memory with a size of 0 can be useful in certain situations, such as when you want to create a zero-length array or when you want to allocate memory that you will later reallocate to a different size using realloc. However, it is important to note that malloc does not guarantee that it will return a pointer to a block of memory that is truly 0 bytes in size. The implementation of malloc may choose to return a block of memory that is larger than the requested size, in which case the additional memory will not be accessible to your program. Clear as mud.
"A little time, a little trouble, your better day" Badfinger
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
It seems to me not only null is the problem, but programming knowledge in general. Throughout my career I've seen very bad code by very "experienced" people. Not just the young kids, but the old farts too. It's so bad I'm now convinced that about 90% of the people are just plain bad at their job :sigh:
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
Nobody teaches to use a debugger, a real one at least. For my first months in the real World I debugged with printf - I did image analysis. Debugging imaging algorithms by printing 1024x1024 tables of numbers? I did that. One of my dreams is to get a teaching position in CS. I will not let anybody out of the room until they learn to place breakpoints and use the watch window.
GCS/GE d--(d) s-/+ a C+++ U+++ P-- L+@ E-- W+++ N+ o+ K- w+++ O? M-- V? PS+ PE Y+ PGP t+ 5? X R+++ tv-- b+(+++) DI+++ D++ G e++ h--- r+++ y+++* Weapons extension: ma- k++ F+2 X
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
Depends on the definition of "young" ;P But, seriously, I see so many powers that be in a high tech company internalize their fears of mistakes by programmers who simply don't get the deeper meaning of a sort-of tri-state logic, so that when when you apply it correctly, you're going to get smacked by individuals who wallow in this fearmongering mindset. Thinking, "if I can't comprehend this to treat the information properly and make a mess, I'm going to force you into that same fear, so that I won't look incompetent and alone". The real issue though, is the hiring policy. Like, who the ***k hired you, and worse, who made you the boss around here? Do you have more skeletons in the closet regarding your pretend-strong, feeble character? Ok I digress. But if you lack the technical grid to understand what your responsibility is towards the state of a variable, you should really be looking for another job. No wonder IT systems have so many vulnerabilities.
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I read somewhere, years ago, that zero/nothing is one of the most difficult concepts for the human brain to understand. I think it was suggested that that was why there is no zero in Roman numerals.
Zero and null are not remotely the same thing. Zero is a value like any other. Null is the absence of any value, "undefined" if you like.
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Zero and null are not remotely the same thing. Zero is a value like any other. Null is the absence of any value, "undefined" if you like.
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
This happens because young programmers learn (at first) languages like python, C#, or other high-level languages right away. Old farts like me have had to put up with C, if not even assembly language. At least on K&R, it is explained what a null pointer is, although my favorite chapter is the one where complicated declarations (which are not complicated at all) are described. It's fine to learn high-level languages right away, but don't we want to take a look at how things work internally? Maybe with the help of the old, decrepit, and "very dangerous" C? I'm not saying to delve into Assembly ... C is sufficient. I am always amazed when I see young computer science students get stunned when I tell them about the two's complement. Old languages may be old and decrepit (though still widely used), but they would still be very useful for many people. To be picky, even high-level languages run on hardware whose principles are still those of John von Neumann's architecture, evolved or not. Many people would still have a lot to learn from "very very very ugly and dangerous" languages like C. And I don't find anything complicated or difficult to understand in malloc(0) either. It must be because I am an old fart. Cheers
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This happens because young programmers learn (at first) languages like python, C#, or other high-level languages right away. Old farts like me have had to put up with C, if not even assembly language. At least on K&R, it is explained what a null pointer is, although my favorite chapter is the one where complicated declarations (which are not complicated at all) are described. It's fine to learn high-level languages right away, but don't we want to take a look at how things work internally? Maybe with the help of the old, decrepit, and "very dangerous" C? I'm not saying to delve into Assembly ... C is sufficient. I am always amazed when I see young computer science students get stunned when I tell them about the two's complement. Old languages may be old and decrepit (though still widely used), but they would still be very useful for many people. To be picky, even high-level languages run on hardware whose principles are still those of John von Neumann's architecture, evolved or not. Many people would still have a lot to learn from "very very very ugly and dangerous" languages like C. And I don't find anything complicated or difficult to understand in malloc(0) either. It must be because I am an old fart. Cheers
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It isn't. I have one apple in my hand. How much do you have in yours? Even prehistoric hunters came back with "zero". There's no 0 in Roman Numerals because it would not make sense to count nothing. A farmer that owes no taxes gets ignored, they counted what was owed. "Zero" would have no use there; even if that is the return of your hunting trip, 0 is not recorded. Writing is too precious to record zero's.
Bastard Programmer from Hell :suss: "If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.
Do you ever really have 0 apples from a weird sort of ship of Theseus-like perspective? Some cultures lack that sort of integer concept from a similar view... all apples are not created equal. No point talking about N of them as the potential distance from reality only increases the further from 1 you get. Forget apples to oranges, they don't even do apples to apples. More recently, quantum physics is saying there is no "nothing" and that there is always "quantum foam" that has always been. Maybe the young ones are so much smarter they look dumb. Nahhh haha. But maybe sending null across a wire as a matter of course is a little bit dumb too.
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
Meh, because often it's a pain in the neck? Look at most languages and the various operators or functions built around 'null'. Then there's things like empty, not set, nothing, and default 'blank' types. Gets into a lot of fun, especially with databases and SQLs. Speaking of fun, and a fun discussion, I had a young programmer use the three values of a boolean. I asked what he was doing. I said go get that switch on the wall to be 'not answered', lol. I'm a firm believer in two boolean values. If you're looking for 3 answers, use a different data type and clearly capture the intent. In my database designs, I leave no null values. Saves that pesky code, lol.
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
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I have just gone through four QA questions, each of which is an error caused by a null reference. And yet none of the posters seems to have any idea a) how to diagnose and fix it, or b) even what the error means. Do those of you who still work in teams find this is a common problem with younger team members?
i tried to explain that to C# students (back when i had a few) by saying that a "null reference" is a named/typed placeholder/slot for a pointer/reference to something which is not defined. you, the programmer, have the "freedom" to create the named/typed slot. and, that the common exception "null reference" was what happened after your running code made demanded/needed/required a defined pointer. you have a favorite metaphor, or explanation ... i am all ears ! of course, now, Visual Studio/C# compiler (and ReSharper) are going to ... suggest a check. and, now, C#/>NET has new Attributes for static Type analysis: [^].
«The mind is not a vessel to be filled but a fire to be kindled» Plutarch
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And so is the color black (assuming an RGB color space). Or anything else represented as binary zeroes in your favorite computer architecture. That two values of completely different semantics have identical same internal representations doesn't imply that the two values are "very much the same thing" - if you just overlook the type/class information. In an OO world, any object instance, regardless of class, having a single member which is set to some value represented as all bits reset is also very much the same thing as a numeric zero. Or a null pointer. If you ignore its semantics, the way you do to claim that zero and null are very much the same thing.
