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In the last call to {{walk()}}, {{dat\[\]}} is treated as a {{Base\[\]}} and the subscripting no longer works correctly when {{sizeof(Derived) \!= sizeof(Base)}}. This is because {{walk()}} incorrectly believes that the size of each element in {{bar\[\]}} is {{sizeof(Base)}}. To locate the second element in the array (located at {{bar\[1\]}}), {{walk()}} adds the {{sizeof(Base)}} to the address {{bar}}. Assuming the derived object is larger (which is often the case), the resulting pointer refers to a point within the first element and not to the start of the second element located at {{bar + sizeof(Derived)}}. |
Compliant Solution
The function walk should use a vector and an iterator. (This is left as an exercise for the reader.)
References
- Meyers 06 Item 3: Never treat arrays polymorphically.
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