Is it good to have all the setter functions return a reference to the object in c++?

Question

Is it good to have all the setter functions return a reference to the object in c++?

Answer 1

It's a usable enough pattern if there's a lot of things that need to be set on an object.

 class Foo
 {
      int x, y, z;
 public:
      Foo &SetX(int x_) { x = x_;  return *this; }
      Foo &SetY(int y_) { y = y_;  return *this; }
      Foo &SetZ(int z_) { z = z_;  return *this; }
 };

 int main()
 {
      Foo foo;
      foo.SetX(1).SetY(2).SetZ(3);
 }

This pattern replaces a constructor that takes three ints:

 int main()
 {
      Foo foo(1, 2, 3); // Less self-explanatory than the above version.
 }

It's useful if you have a number of values that don't always need to be set.

For reference, a more complete example of this sort of technique is refered to as the "Named Parameter Idiom" in the C++ FAQ Lite.

Of course, if you're using this for named parameters, you might want to take a look at boost::parameter. Or you might not...