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copied!<p>I know I'm a year late and a dollar short, but I'll pitch in my solution anyways.</p> <pre><code>//////// Base.. template<typename DerivedBuilder, typename Options> class Builder { protected: Builder() {} DerivedBuilder& me() { return *static_cast<DerivedBuilder*>(this); } Options options; }; ////////////////////////// A ////////////////////////// class Options_A { public: Options_A() : a(7) {} int a; }; class Builder_A; class A { public: virtual ~A() {} virtual void print() { cout << "Class A, a:" << a << endl; } protected: friend class Builder_A; A(const Options_A& options) : a(options.a) {} int a; }; template<typename DerivedBuilder, typename Options = Options_A> class BuilderT_A : public Builder<DerivedBuilder, Options> { public: using Builder<DerivedBuilder, Options>::options; using Builder<DerivedBuilder, Options>::me; DerivedBuilder& a(int p) { options.a = p; return me(); } }; class Builder_A : public BuilderT_A<Builder_A> { public: shared_ptr<A> create() { shared_ptr<A> obj(new A(options)); return obj; } }; ////////////////////////// B ////////////////////////// class Options_B : public Options_A { public: Options_B() : b(8) {} int b; }; class Builder_B; class B : public A { public: virtual ~B() {} virtual void print() { cout << "Class B, a:" << a << ", b:" << b << endl; } protected: friend class Builder_B; B(const Options_B& options) : A(options), b(options.b) {} int b; }; template<typename DerivedBuilder, typename Options = Options_B> class BuilderT_B : public BuilderT_A<DerivedBuilder, Options> { public: using Builder<DerivedBuilder, Options>::options; using Builder<DerivedBuilder, Options>::me; DerivedBuilder& b(int p) { options.b = p; return me(); } }; class Builder_B : public BuilderT_B<Builder_B> { public: shared_ptr<B> create() { shared_ptr<B> obj(new B(options)); return obj; } }; ////////////////////////// C ////////////////////////// class Options_C : public Options_B { public: Options_C() : c(9) {} int c; }; class Builder_C; class C : public B { public: virtual ~C() {} virtual void print() { cout << "Class C, a:" << a << ", b:" << b << ", c:" << c << endl; } protected: friend class Builder_C; C(const Options_C& options) : B(options), c(options.c) {} int c; }; template<typename DerivedBuilder, typename Options = Options_C> class BuilderT_C : public BuilderT_B<DerivedBuilder, Options_C> { public: using Builder<DerivedBuilder, Options>::options; using Builder<DerivedBuilder, Options>::me; DerivedBuilder& c(int p) { options.c = p; return *static_cast<DerivedBuilder*>(this); } }; class Builder_C : public BuilderT_C<Builder_C> { public: shared_ptr<C> create() { shared_ptr<C> obj(new C(options)); return obj; } }; /////////////////////////////////////////////////////////////////////////// int main() { shared_ptr<A> a = Builder_A().a(55).a(1).create(); a->print(); shared_ptr<B> b = Builder_B().b(99).b(2).a(88).b(4).a(2).b(3).create(); b->print(); shared_ptr<C> c = Builder_C().a(99).b(98).c(97).a(96).c(6).b(5).a(4).create(); c->print(); return 0; } /* Output: Class A, a:1 Class B, a:2, b:3 Class C, a:4, b:5, c:6 */ </code></pre> <p>C derives from B, and B derives from A. I've repeated parameters to show they can put in any order desired. </p>

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