There is no equivalent to 'operator overloading' (as found in C++ for example), in Processing or Java. Personally, I think this is a good thing that one cannot overload as it makes code easier to debug. Yes, marginally more verbose in some circumstances, but less effort in the long run.

There are some minor exceptions built into the language, most notably '+' is used as a string concatenation operator. And note you can apply normal arithmetic operators to all the numeric primitives (so double, short, and long as well as int and float). You can also apply these to their 'wrapper' classes, Integer, Float, Double etc. as these are automatically converted to their primitive types before arithmetic is applied.

BTW: A minor style point, if you are defining methods to do the arithmetic operations, they should, as with all methods/functions start with a lower-case latter. so cMult(a,b), not CMult(a,b).