int Mask( int x )
{
} // Mask( )

This function should return an integer with a 1 corresponding to x's least significant 1 bit; read: x's rightmost 1. I can't use control structures, and I can only use the operands ! ~ | ^ & << >> and +. If anyone has any tips, I'd appreciate it.

Oh, I smell a University student.

This is kinda nasty. I remember finding this in a book somewhere. What you do is something like this:

You get an integer, say 13 = 1101. The least significant bit is the rightmost bit, i.e. 1, yes (forgot most of this stuff ages ago)?

13 & 1 = 1 - rightmost
12 & 1 = 0 - rightmost (12 = 1100)

What this does is compare the following
13 = 1101
& 1 = 0001
===========
1 = they're the same

Hope this helps
GF