2/9/2024 0 Comments Java for loop iterator syntaxWhile Map is part of the Collections API, it doesn’t extend any parent interface. Thus, always pay close attention to wording to be sure you don’t miss a detail of this type. Even though the Java certification exam tries to avoid using cannot, the word can appear. In this question, however, we allowed ourselves to use cannot to simplify the question by requiring only a single correct answer. Such negatives are a little unfair, and the exam generally tries to avoid them. This means that option A is incorrect.Īs a side note, notice that option A says cannot. Basically, all classes that implement, and therefore anything that implements, can be used with the enhanced for loop. Returning to the fact that the enhanced for loop can operate on any array or any type that implements the interface, HashSet implements the Set interface, which extends the Collection interface, which extends the Iterable interface. Therefore, because the enhanced for loop must work consistently in all valid cases, including those without an index position, the notion of an index does not form part of the enhanced for loop. Although it’s common to iterate arrays and lists, which have a specific order to their elements, an index has no real meaning with a set or with any other Iterable that doesn’t keep its contents in an explicitly ordered structure. Specifically, the enhanced for loop is able to iterate over arrays and anything that implements the interface Iterable. With this higher level of abstraction comes a separation from specific implementations, and with it, a loss of some familiar detail. This focus on what should be achieved rather than how to achieve it is what is meant by a higher level of abstraction. The details of how the loop is controlled are handled automatically. Using the enhanced for loop, developers simply indicate the intention of processing each item from a data set. The enhanced for expression provides a higher level of abstraction iterating over the elements of an Iterable (for example, a Set or a List) or an array than the traditional simple for statement.ĭevelopers using the simple for statement must explicitly describe how the runtime should iterate, such as by declaring a loop and a counter variable, incrementing the counter, and comparing it against the maximum count to control progress through the data and to terminate the iteration at the right point. The loop supports deletion of the current element during execution of the loop.Įarly termination of the loop via a break statement is prohibited.Īnswer. The loop does not provide access to the index of the current element. Which of the following is true about Java’s enhanced for statement? Choose one. The enhanced for statement operates at a higher level of abstraction than the traditional simple for statement.
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