C++ base-class constructor vs member-object constructor: trace printed members. #include <iostream.h> class CuriousTabBase { public: int x, y; CuriousTabBase(int xx = 0, int yy = 0) { x = xx; y = yy; } }; class CuriousTabDerived : public CuriousTabBase { private: CuriousTabBase objBase; public: CuriousTabDerived(int xx, int yy) : CuriousTabBase(xx), objBase(yy) { cout << this->x << " " << this->y << " " << objBase.x << " " << objBase.y << " "; } ~CuriousTabDerived() {} }; int main() { CuriousTabDerived objDev(11, 22); return 0; }

Introduction / Context: The problem probes constructor initializer lists for a derived class and a contained member object. It checks whether you can follow which values are passed to the base subobject versus the member subobject and how defaulted parameters are used.

Given Data / Assumptions:

• CuriousTabBase(xx = 0, yy = 0) stores x = xx, y = yy.
• CuriousTabDerived(int xx, int yy) : CuriousTabBase(xx), objBase(yy).
• Prints: this->x, this->y, objBase.x, objBase.y.

Concept / Approach: The base subobject of CuriousTabDerived receives only xx, so xx maps to x and the default yy = 0 sets base y to 0. The member object objBase(yy) receives yy as its first argument (xx), while its own second parameter defaults to 0. So objBase.x = yy and objBase.y = 0.

Step-by-Step Solution:

Verification / Alternative check: If the base initializer were CuriousTabBase(xx, yy) then this->y would be 22; if objBase were constructed as objBase(yy, yy) then objBase.y would be 22. Neither is done here.

Why Other Options Are Wrong:

• 11 22 0 0: assigns yy to base y, which does not happen.
• 11 0 0 22: swaps x/y mapping for objBase.
• 11 22 11 22: would require passing both parameters to both ctors.
• Compile error: none present.

Common Pitfalls: Forgetting that default parameters fill omitted ctor args; confusing base-subobject initialization with member-object initialization.

Final Answer: 11 0 22 0