Posted By: Zaba (I'd rather be skiing!) on 'Humor' Title: software engineering joke - viva OO Date: Tue Nov 7 15:09:09 2000 > Once upon a time, in a kingdom not far from here, a king summoned two of > his advisors for a test. He showed them both a > shiny metal box with two slots in the top, a control knob, and a lever. > "What do you think this is?" > > One advisor, an engineer, answered first. "It is a toaster," he said. > The king asked, "How would you design an embedded > computer for it?" The engineer replied, "Using a four-bit > microcontroller, I would write a simple program that reads the > darkness knob and quantizes its position to one of 16 shades of > darkness, from snow white to coal black. The program would > use that darkness level as the index to a 16-element table of initial > timer values. Then it would turn on the heating elements and > start the timer with the initial value selected from the table. At the > end of the time delay, it would turn off the heat and pop up > the toast. Come back next week, and I'll show you a working prototype." > > The second advisor, a computer scientist, immediately recognized the > danger of such short-sighted thinking. He said, > "Toasters don't just turn bread into toast, they are also used to warm > frozen waffles. What you see before you is really a > breakfast food cooker. As the subjects of your kingdom become more > sophisticated, they will demand more capabilities. They > will need a breakfast food cooker that can also cook sausage, fry bacon, > and make scrambled eggs. A toaster that only makes > toast will soon be obsolete. If we don't look to the future, we will > have to completely redesign the toaster in just a few years." > > "With this in mind, we can formulate a more intelligent solution to the > problem. First, create a class of breakfast foods. > Specialize this class into subclasses: grains, pork, and poultry. The > specialization process should be repeated with grains > divided into toast, muffins, pancakes, and waffles; pork divided into > sausage, links, and bacon; and poultry divided into > scrambled eggs, hard-boiled eggs, poached eggs, fried eggs, and various > omelet classes." "The ham and cheese omelet class is > worth special attention because it must inherit characteristics from the > pork, dairy, and poultry classes. Thus, we see that the > problem cannot be properly solved without multiple inheritance. At run > time, the program must create the proper object and > send a message to the object that says, 'Cook yourself.' The semantics > of this message depend, of course, on the kind of > object, so they have a different meaning to a piece of toast than to > scrambled eggs." > > "Reviewing the process so far, we see that the analysis phase has > revealed that the primary requirement is to cook any kind of > breakfast food. In the design phase, we have discovered some derived > requirements. Specifically, we need an object-oriented > language with multiple inheritance. Of course, users don't want the eggs > to get cold while the bacon is frying, so concurrent > processing is required, too." > > "We must not forget the user interface. The lever that lowers the food > lacks versatility, and the darkness knob is confusing. > Users won't buy the product unless it has a user-friendly, graphical > interface. When the breakfast cooker is plugged in, users > should see a cowboy boot on the screen. Users click on it, and the > message 'Booting UNIX v. 8.3' appears on the screen. > (UNIX 8.3 should be out by the time the product gets to the market.) > Users can pull down a menu and click on the foods they > want to cook." > > "Having made the wise decision of specifying the software first in the > design phase, all that remains is to pick an adequate > hardware platform for the implementation phase. An Intel 80386 with 8MB > of memory, a 30MB hard disk, and a VGA > monitor should be sufficient. If you select a multitasking, object > oriented language that supports multiple inheritance and has a > built-in GUI, writing the program will be a snap. (Imagine the > difficulty we would have had if we had foolishly allowed a > hardware-first design strategy to lock us into a four-bit > microcontroller!)." > > The king wisely had the computer scientist beheaded, and they all lived > happily ever after. Zaba P.S.: Put some excitment between your legs - ride a mountain bike!
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