Is there a term for operators which modify operands?

Question

I believe most operators will not modify their operands. If I want to ask if an operator is one of those that will alter it's operands, is there a word I can use that means that? For example:

Is the bitshift operator a [adjective that means "it will change the operand"]

or

The '+' operator will not modify a variable, but changing it to '+=' will change the varable on the left, because '+=' is a [need that word again, this time in noun form]

Answer 1

Generally, unary operators and some shorthand operators are those which are used to change the operand.

++a;
--a;
a++;
k +=30;
k -=30;

etc.