F16s and Programming

The F16 Fighting Falcon is quite an impressive aircraft given that its design is over 20 years old. It was designed to replace the wreckage that was the F4 Phantom, the plane which seriously underperformed in Vietnam. The F16 was originally designed to be a one seater plane, and was built with negative stability. Negative stability basically means if you don't do anything, the plane will go out of control (sort of like Phils old car:) ) However negative stability also means you can do pretty impressive things, as it gives you extra maneuverability at high speeds. (sort of like Phils new car:) ) A side effect of this maneuverability is that it makes the aircraft suitable for localised bombing on small targets, and as a result the F16B was developed as 2 seater plane for precisely this reason. All in all its a pretty high performance fighter plane.

Side effects is what I will be talking about here (yes I realise thats a highly tenuous made-up link). Non nerds can stop reading now . So, I presume you are familiar with the C++ Macro & Preprocessor facility to apparently aid people while programming. Basically if you use something like a character very regularily to represent a flag, you can do things like...

typedef char FlagType;

Which makes your code more readable to the independent observer. Another thing you can do is define macros, i.e. very small frequently used functions. Something like

#define ABS(X) ((X) >= 0 ? (X) : -(X))

Now allows you to use ABS inline, and if you've overloaded your operators accordingly, you can now call ABS on anything that understands the >= and -. I've never used these macros much, mainly because I've never had to write uber-optimised code but I am also wary of them. Why am I wary, well mainly cause of ones like this...

#define Cube(a) a*a*a

Cubing is a fairly trivial problem, no super serious hacks involved. So whats wrong with the above piece of code? Answers in the comment box. I expect you all to have a go at this. Its a simple problem.

Easter Egg: How many computer science Acronyms can you find in this article? Seriously, find ten please!

Update: Dave has posted a good reason why the above #define will not work. Read about it in the comments.

Daves answer is #define Cube(a) ((a)*(a)*(a))

which is correct, Why wouldn't this work?

#define Cube(a) (a)*(a)*(a)