Programming question in C

[Concrete Geist]

This question has got me baffled, and I want to know how it would be done, so could an experienced programmer show how this is accomplished?? thanks.

Define a preprocessor macro swap(t, x, y) that will swap two arguments x and y of a given type t.

[jkm]

x ^= y
y ^= x
x ^= y

swaps two variables using xor.

as for the type, i'm not quite sure what would be necessary for that.

#define swap(x,y) x^=y;y^=x;x^=y

[pinoy]

#define swap(t, x, y) \
do { t tmp = x; x = y; y = tmp; } while(0)

[bdg1983]

:cool: c++ template functions :cool:

[pinoy]

template <typename T> swap(T a, T b) { T c = a; a = b; b = c; }

[jemfinch]

Originally posted by pinoy:

template <typename T> swap(T a, T b) { T c = a; a = b; b = c; }


Shouldn't those function arguments be passed by reference?

Jeremy

[pinoy]

Originally posted by jemfinch:
<STRONG>
template &lt;typename T&gt; swap(T a, T b) { T c = a; a = b; b = c; }
&lt;HR&gt;&lt;/BLOCKQUOTE&gt;

Shouldn't those function arguments be passed by reference?

Jeremy</STRONG>

You're right, they should be. Most of my code posted here are not tested :(
Thanks for pointing that out.

[pinoy]

Originally posted by jkm:
<STRONG>x ^= y
y ^= x
x ^= y

swaps two variables using xor.

as for the type, i'm not quite sure what would be necessary for that.

#define swap(x,y) x^=y;y^=x;x^=y</STRONG>

This only works for integral type. and doesn't work when used in an unbracketed if block.