Early-on in their studies, many students often ask me (Matthew Mead) questions such as "why do we need to know this?", "when are we going to use this?", or "what good is a stack?" etc. Just as a small child must first learn to crawl and then to stand upright before walking, students beginning their journey into computer science and the art of computer programming must first learn the fundamentals. This can be frustrating to the new student because she is often familiar with more grand and complex programs and wonders how the trivial, and often contrived, programs she writes during the introductory programming courses have any purpose in the "real world." Learning to run is easy if one knows how to walk. Aristotle (BC 384-322) said it best:
The roots of education are bitter, but the fruit is sweet.
Like most disciplines, there is much to be said about experience, and computer programming is no exception. There is a major difference between a novice programmer and an experienced programmer. Also, there is generally a fundamental difference between a programmer that is self-taught and one that is formally trained. This is not to say that all programmers that lack formal schooling are somehow less prepared or less qualified than their formally-trained counterparts. On the contrary, self-taught people must be highly-motivated and goal-oriented to learn concepts that most people enroll others to teach them. This also does not imply that all formally-trained programmers are superior to informally-trained programmers. You can make a case for both sides.
In 1971, Gerald M. Weinberg wrote a classic book entitled The Psychology of Computer Programming. Although it is now over 30 years old, there is still much that one can glean from it. Below is a section from the book in which the author describes the differences between professional programming and amateur programming. In his book, Weinberg makes a few references to out-dated technologies and practices, but you can still understand where he's coming from.
Professional versus Amateur Programming
The high school student and the engineer represent two ends of a rich spectrum of programmers. These ends may or may not be different, but nothing antagonizes the professional programmer more than to hear an amateurhaving just completed a six-statement program in BASIC to find roots of a quadratic equationdiscourse on the theory and practice of programming. We know well, of course, that this vehemence could be a symptom of lack of any difference between the two activities, for such a lack would put the professional in a much diminished stature. Although some professional programmers may indeed be no more than hacks camouflaged by esoteric obscurities and some amateurs might be able to gain a deep appreciation of programming through writing of a single short program, there is a difference.
Perhaps the deepest differences emanate from differences in the ultimate user of his program. Almost invariably, the sole intended user of an amateur's program is the amateur himself, whereas the professional is writing programs which other people will use. To be sure, the professional oftentimes finds himself writing a program for his own useto generate test data or to evaluate the performance of an untried algorithm, to name but two instances. And, indeed, when doing this kind of work, the professional commonly slips into amateurish practices. But the main thrust of his work is directed toward use of the program by other people, and this simple fact conditions his work in a number of ways.
Because the amateur will be the user of his own program, he has the choice of doing his thinking either before or after programming. Consider, for example, a student who wants to write a program to find roots of quadratic equations. Ideally, he is sitting at a terminal, for terminals are well suited to post-programming thought. He decides that he will probably need some input. This requires that he choose some names for variables. Here the small size of the program and its complete isolation from other programs give him a big boostwithout his awareness, of coursefor he may choose whatever names first come to mind, such as a, b, and c. In simply following the notation of high school algebra, he does not think at all about possible conflicts with other symbols, standards which must be observed, or even with declaration attributes. No, he merely types something like
GET LIST (A, B, C);After adding some other program parts in a similar way, he will be ready to try his program. Upon initiation of processing, the terminal will pause in request for data. Since it is his own program, he does not need any prompting about what data are expected at this time, so he saved at least such coding as a preliminary
PUT LIST ('ENTER A, B, AND C');He also knows the order in which things are required, and the simplified input system of his language permits him to enter his data in such diverse forms as
1 2 3Moreover, if he should happen to slip and enter
1, 2, 3
1.0, 2.0, 3.0
1E0, 2.0E+0, .3E+1
1A, 2, 3The system will reject the first value without his having had to program an error-handling routine or document the reasons why such a data item is rejected. He knows what is expected, for he wrote the program.
Even more subtle problems can be handled for him because he can think after programming. When he enters such a case as 1, 2, 3, he will probably find that some later statement coughs up the data because he will be trying to take the square root of a negative number (b2-4ac). He gets the diagnostic automaticallywithout any forethought or foreprogrammingand probably realizes rather quickly what the problem is. He may then simply decide that he doesn't want complex roots anyway, in which case the problem disappears by definition. Only when the programmer himself is defining the problem is this sort of simplification possible, for the professional programmer would at least have had to leave the terminal and find someone to authorize a change or clarification of specifications.
If the amateur does decide that he needs complex roots, his task is still much simpler than that of the professional in making the necessary modifications. Even when he has finished the program, his job remains simpler, for when he is finished, he merely has to forget about it. The professional, on the other hand, has to put it into a neat package and send it out into the cold worldfrom which it may return to him bearing caustic comments, comments whose sense has to be considered for subsequent modifications. A true professional, of course, would have constructed the program in such a way that modifications will not be overly involvedbut that was another thing he had to think about when writing.
Even if the program is not intended for other eyes at all, the professional cannot forget about it in the same way as the amateur. For instance, if the program is just stored in the terminal system, the user will eventually receive notification to clean up his storage. The professional has to recall each of the programs in his library, for some will still be needed. That amateur, however, probably has only one program, so he instructs the system to erase itor lets the erasure be done automatically by default. But woebetide the professional who lets the system erase his library! No, he must drop what he is doing and check his long library list before the deadline comes around, or all his work will be gone with the wind.
Many years ago, when programming systems were rudimentary, the difference between the professional and amateur was not nearly so pronounced. Today, however, so many of the things that amateurs want to do have been made implicit in our systems that the gulf is a wideand wideningone. Paradoxically, however, as the gulf has widened, the amateurs have become less and less aware of it, for they have become less and less aware of what the system is doing for them. Just as a good manager faces the problem that his employees are unaware of his management, so does the systems designer suffer because the better his system does its job, the less its users know of its existence.
And speaking of managers, they can be the most amateur of amateurs when it comes to programming. A few years ago, one firm decided to try to give its executives a course that would make them appreciate the problems of their professional programmers. Inasmuch as these were executives, each was assigned a professional programmer as "assistant" for the duration of the course, the climax of which was a problem which each executive had to program "for himself."
To enhance the executives' appreciation for the problems faced by programmers, this work session was interrupted by frequent trivial phone calls, meetings, and small changes in specifications. The executives got the pointthat executives could increase programmer productivity by "sheltering" their staff rather than being the major source of disturbance. But they also took away anotherdeeper rootedidea. After all, in spite of all these disturbances, they had managed to get their program working, hadn't they? Sure, they had a little help from their "assistants", but not much, really. So, if they could get a program done on time, why couldn't their programmers? And what was so hard about programming, anyway, if they could master it in a week?
This entire impression was based on a combination of illusions of the same sort that make any amateur unable to appreciate the abyss which separates him from the professional. First, there was the semantic illusion which equates the "program" they wrotea trivial problem involving compound interest calculation which could have been better solved using a log table or slide rulewith the "programs" written by their staffoperating systems, compilers, utilities, and the like. Second, there was the illusion that their assistants were "not helping them much"an illusion based on the lack of understanding of the complexities of programmingthe very complexities which the assistants were supposed to shield them from lest they take away a bad feeling about programming engendered by being unable to complete their little problem. And so, the very efforts directed at giving the executives a better appreciation for the problems of the programmer resulted in precisely the opposite effect.
Better appreciation of programming by managers is needed: a case in point is the fact that a manager could even begin to believe that he could learn in a week what the professional has learned through years of experience. Indeed, it is a homily that the difference between the professional and the amateur programmer lies in the superior past experience of the professional. But one could also contend that an equally important difference lies not in the programs each has previously written, but in those he will write in the future. The amateur, being committed to the results of the particular program for his own purposes, is looking for a way to get the job done. If he runs into difficulty, all he wants is to surmount itthe manner of doing so is of little consequence. Not so, however, for the professional. He may well be aware of numerous ways of circumnavigating the problem at hand. He may even employ one of them for the immediate purpose of getting the job done. But his work does not stop there; it begins there. It begins because he must understand why he did not understand, in order that he may prepare himself for the programs he may someday write which will require that understanding.
The amateur, then, is learning about his problem, and any learning about programming he does may be a nice frill or may be a nasty impediment to him. The professional, conversely, is learning about his professionprogrammingand the problem being programmed is only one incidental step in his process of development.
The other side of this observation is that the professional never quite takes any problem as seriously as does the amateur. He has had bugs before, and he will have them again. This difference in attitude is a source of constant friction between the two types: the professional is very tired and a bit irritated by the unending stream of amateurs waving their printouts in his face and condemning the machine, the operator, the system, the keypuncher, the language, or the government. The amateur, on the other hand, can see that the professional does not even care that his means and standard deviations are not going to be ready in time for inclusion in the proceedings of the conference.