From: tyan@cs.cornell.edu (Thomas Yan)
Newsgroups: cornell.class.cs100
Subject: Idiom for swapping two variables
Date: 2 Feb 2000 20:05:05 GMT

in section last week, you should have seen this 
idiom (common, well-known code sequence) for swapping
two int variables x and y:

    int tmp;
    tmp = x;
    x = y;
    y = tmp;

this is something you should be able to do/use without thinking
hard about it.

[remark:

this is perhaps not so well-known, but if you want to "toggle"
variable x between two values A and B, i consider this to be
a nice way to do it:

   x = A + B - x;
]