korn.hin

来自「1984-1993模糊 C 源代码竞赛.zip 非常的好,不过这是DOS格式,」· HIN 代码 · 共 45 行

Best One Liner: <ulysses!dgk> David Korn

	David Korn
	AT&T Bell Labs
	MH 3C-526B, AT&T Bell Labs
	Murray Hill, NJ
	07974
	USA

The Judges believe that this is the best one line entry ever received.
Compile on a UN*X system, or at least using a C implementation that
fakes it.  Very few people are able to determine what this program
does by visual inspection.  I suggest that you stop reading this
section right now and see if you are one of the few people who can.

Several points are important to understand in this program:

	1) What is the symbol `unix' and what is its value in the program?
	   Clearly `unix' is not a function, and since `unix' is not declared
	   to be a data type (such as int, char, struct foo, enum, ...)
	   what must `unix' be?

	2) What is the value of the symbol "have"?  (hint: the value is
	   NOT 4 characters, or 'h', or a string)  Consider the fact that:

		char *x;

	  defines a pointer to a character (i.e. an address), and that
	  the `=' assigns things is compatible types.  Since:

	        x = "have";

	  is legal C, what type of value is "have"?

	3) Note that the following expressions yield the same value:

		x[3]	*(x+3)	  *(3+x)

	   since addition is communitive.  What can be said about the value:

		3[x]

David Korn's /bin/ksh provides us with a greatly improved version of
the /bin/sh.  The source for v7's /bin/sh greatly inspired this contest.