Data Structures and Algorithm Analysis - Computer Science at ...

132 Chap. 4 Lists, Stacks, and Queues/** The Dictionary abstract class. */public interface Dictionary {/** Reinitialize dictionary */public void clear();/** Insert a record@param k The key for the record being inserted.@param e The record being inserted. */public void insert(Key k, E e);/** Remove and return a record.@param k The key of the record to be removed.@return A maching record. If multiple records match"k", remove an arbitrary one. Return null if no recordwith key "k" exists. */public E remove(Key k);/** Remove and return an arbitrary record from dictionary.@return the record removed, or null if none exists. */public E removeAny();/** @return A record matching "k" (null if none exists).If multiple records match, return an arbitrary one.@param k The key of the record to find */public E find(Key k);/** @return The number of records in the dictionary. */public int size();};Figure 4.29 The ADT for a simple dictionary.Figure 4.29 shows the definition for a simple abstract dictionary class. Themethods insert and find are the heart of the class. Method insert takes arecord and inserts it into the dictionary. Method find takes a key value and returnssome record from the dictionary whose key matches the one provided. If there aremultiple records in the dictionary with that key value, there is no requirement as towhich one is returned.Method clear simply re-initializes the dictionary. The remove method issimilar to find, except that it also deletes the record returned from the dictionary.Once again, if there are multiple records in the dictionary that match the desiredkey, there is no requirement as to which one actually is removed and returned.Method size returns the number of elements in the dictionary.The remaining Method is removeAny. This is similar to remove, exceptthat it does not take a key value. Instead, it removes an arbitrary record from thedictionary, if one exists. The purpose of this method is to allow a user the abilityto iterate over all elements in the dictionary (of course, the dictionary will becomeempty in the process). Without the removeAny method, a dictionary user could