Determine if all decimal digits are unique Deleted questions on Stack Overflow sometimes make for great golf material.

Write a function that takes a nonnegative integer as input, and returns true if all the digits in the base 10 representation of that number are unique. Example:

48778584 -&gt; false
17308459 -&gt; true


Character count includes only the function.

If you choose to answer in C or C++: no macros, no undefined behaviour; implementation-defined behaviour and compiler warnings are fine.
Golfscript, 8 7 characters:

{`..&amp;=}



` - stringify the argument
.. - clone twice
&amp; - intersect with itself (remove duplicates)
= - check for equality.


if the function needs to be named (10 9 characters):

{`..&amp;=}:a


if a program suffices (5 4 characters):

..&amp;=