Life cycle of a sensor object

Understanding C++ object construction and destruction in practice

This is a medium-difficulty C++ language-knowledge question that tests your ability to trace the lifecycle of objects—specifically, when constructors and destructors are called, and in what order. It's the kind of question designed to separate candidates who have read about C++ semantics from those who've internalized them through practice.

To solve problems like this, you need to mentally execute the code line by line, tracking each object's scope, noting which constructors fire as objects are created, and which destructors fire as they go out of scope. Pay close attention to temporary objects, function arguments, and return values, as these are common sources of mistakes. The question rewards careful reasoning over guessing.

• Constructor and destructor invocation order
• Object scope and lifetime rules
• Temporary object semantics
• Copy semantics vs. move semantics