How does taking modulo 1 make sense? I need some help understanding the problem statement in CLRS 11.3-4 pg 269.  It says:


  Consider a hash table of size $m = 1000$ and a corresponding hash function 
   $ h(k) =\left \lfloor m(kA \bmod 1) \right \rfloor $
  for $A = (\sqrt5 - 1)/2$. Compute the locations to which the keys
  61, 62, 63, 64, and 65 are mapped.


Is $\mod 1$ a misprint in my copy? Also $A$ is a real number.  Is modulus defined for non-integer numbers?
That's not a misprint.  $kA \bmod 1$ makes sense.  For instance, $37.239 \bmod 1 = 0.239$.