Obfuscated SWAP: not portable!

[DAVID NEWALL]

In article <149 at cpsolv.UUCP>, rhg at cpsolv.UUCP (Richard H. Gumpertz) writes:
> The exchange of x and y that has been under discussion:
>     x ^= y ^= x ^= y
> is non-portable because it depends on right-to-left evaluation which is NOT
> specified in the C standard.

I think it is specified.  (Perhaps it depends on whose standard you follow?)

K&R I, page 19:
     "The line
        nl = nw = nc = 0;
    sets all three variables to zero.  This is not a special case, but a
    consequence of the fact that an assignment has a value and assignments
    associate right to left."

David Newall                     Phone:  +61 8 343 3160
Unix Systems Programmer          Fax:    +61 8 349 6939
Academic Computing Service       E-mail: ccdn at levels.sait.oz.au
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