Today I've seen the following pattern: you have an object A and an object B. Object B accepts a pointer to A at its constructor.

Once B is created, there's a method B.doCalc() that performs a calculation (internally using A's information). The result is obtained with method B.getResult().

In order to perform another calculation, A is modified, and B.doCalc() is called again.

What is your opinion on this choice ? I would have designed it differently, but I want to hear your voice.

Edit : note that my main objection is to modify A to have a different result from B, without touching B.

Although similar, I think that just this discipline expresses a much better feeling of what's going on. Instead of

a = new A
a.whatever = 5
b = new B(a)
b.doCalc()
res = b.getResult()
a.whatever = 6
b.doCalc()
res = b.getResult()

You get the a pointer object from b itself.

a = new A
a.whatever = 5
b = new B(a)
b.doCalc()
res = b.getResult()

a = b.getAPointer()
a.whatever = 6
b.doCalc()
res = b.getResult()

because it makes more explicit the fact that a is taken from b and then modified. I still don't like it, though...