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What this C++ code-reading question tests

This is a medium-difficulty code-reading question that asks you to trace execution and predict output. It focuses on your ability to reason carefully through C++ semantics, particularly around object construction, data organization, and how state changes propagate through a program.

To solve problems like this, you need to follow the control flow precisely, track variable state at each step, and understand how language features like constructors, container operations, and data layout affect the final result. Interviewers use these questions to confirm you think rigorously about code behaviour rather than relying on intuition.

• Object lifecycle and initialization in C++
• Container semantics and element access
• State mutation and side effects