What we could use are:
Unary operators+, -, !, ~, ++, --, true, false
Binary operators
+, -, *, /, %, &, |, ^, <<, >>
Comparison operators
==, !=, <, >, <=, >=
What we can't use are:
conditional logical operators
&&, ||
array indexing operator
[]
cast operator
()
Assignment operators
+=, -=, *=, /=, %=, &=, |=, ^=, <<=, >>=
Extra
=, ., ?:, ->, new, is, sizeof, typeof