Implementation: Modifications During Iteration

• Items added during iteration
• Mathematical “closure” algorithm relies on hitting added items later.
• Other algorithms rely on not hitting them.
• Prioritized list relies on hitting high priority added items immediately, and low priority added items later.
• Items deleted during iteration
• Common mistake is to iterate list, deleting items.
• Don’t allow this to crash your iterator.
• See also: http://sw-eng.falls-church.va.us/AdaIC/docs/style-guide/83style/style-t.txt