Hi,

I have an object A and pass it some function that calls its setters to reset some data members.

e.g.

void A(B b){ b.SetWhatever(2)}

then after calling A b indeed has the parameters reset. The problem comes when I pass b to a function C that calls A. Now inside C, b again has had its parameters changed. But externally to C b has not had its parameters changed,

e.g

void C(B b){ A(b) ;}

why does b have different values for its data members inside C, than outside C? After all in both places it is residing at the same memory address surely?

Thanks,

Mark

Why don't *you* check if they have same address?

Simple rule: If you want changes made by a function to one of its argument to be visible to the caller of that function, that argument should be passed by reference or by pointer. If you are using objects that are big and/or costly to construct you always pass those by reference or pointer, only make the parameter const if you don't intend to change the state of the object in the function.