I saw one that didn''t use a temp variable, it xored the variables or something, is anyone familiar with this? if you can remember how it was written, i''d appreciate it. thanks

int a = 10, b = 20;
a = a ^ (b = (b ^ (a = (a ^ b))));

Afterwards: a = 20, b = 10.


Null and Void
"In this house we obey the laws of thermodynamics!" --Homer Simpson

Please use temp variables, expressions like that make my brain start to boil

because of the problem, that you couldnt use binary operators onto floats, you could use the macro like this:

#define SWAP(a,b) {(*((int*)&a))^=(*((int*)&b));(*((int*)&b))^=(*((int*)&a));(*((int*)&a))^=(*((int*)&b));}

working for floats, too (it just reads the floats like ints, thats all, but its working, and thats what we want)

we wanna play, not watch the pictures

quote: Original post by goir

Please use temp variables, expressions like that make my brain start to boil

Agreed. And davepermen''s is even more of a brain boiler. Wasn''t there a xchange assembler command (swap two 32 bit values)? I''m sure I read about it somewhere and if we get away from macros like this...

how could that float version of swap possibly be worth it? six type conversions, and alot of pointer dereferences..

------------------------
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No one ever said that the macro was faster =P

Null and Void
"In this house we obey the laws of thermodynamics!" --Homer Simpson

it works, that was all what I wannted to show, but, yep, its stupid, and a inline like that is bether

inline void swap(int& x,int& y)
{
int buffer=x;
x=y;
y=buffer;
}

because you could even use it for big classes (just overload it)

we wanna play, not watch the pictures

Why not something like this:

    template <class T> inline void swap(T & op1, T & op2){   T temp = op1;   op1 = op2;   op2 = temp;}    

quote:
Why not something like this:

Because std::swap already does this, and it''s specialised for some things (e.g. std::vector)