Mastering C++: A Comprehensive Quiz Based on 'Thinking in C++'

Under what condition should self-assignment be checked in overloaded assignment operators?

1. When the operator modifies its left-hand operand

2. When dealing with dynamic memory allocation

3. Always as a general guideline

4. Only when the class involves textbook management

The correct answer is: Always as a general guideline

Self-assignment should always be checked in overloaded assignment operators as a general guideline. Self-assignment can occur when an object is assigned to itself, which can lead to issues such as memory leaks or loss of data. While self-assignment may not be a common occurrence, it is important to handle it properly in case it does happen. Option A is incorrect because the operator modifying its left-hand operand does not necessarily mean self-assignment is involved. Option B is incorrect because self-assignment should be checked regardless of whether dynamic memory allocation is involved. Option D is incorrect because self-assignment can occur in any class, not just ones involving textbook management.