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

How does the 'iterator' advance its position in the prefix form?

1. By adding one to the index before returning the element

2. By subtracting one from the index before returning the element

3. By multiplying the index

4. By returning the element and then adding one to the index

The correct answer is: By adding one to the index before returning the element

The 'iterator' is a function used to traverse through a data structure and access its elements. It maintains a reference to the current position in the structure and moves forward as needed to access the next element. In the prefix form, the iterator advances its position by first adding one to the index and then returning the element at that index. This ensures that each subsequent call to the iterator will access the next element in the structure. Therefore, options B and C are incorrect as they involve subtracting and multiplying the index, which would not result in advancing to the next element. Option D is also incorrect as it involves returning the element first and then advancing the position, which would result in accessing the same element repeatedly. Hence, option A is the correct way for the 'iterator' to advance its position in the prefix form.