1. Dictionaries Chapter 17 Slides by Steve Armstrong LeTourneau University Longview, TX  2007,  Prentice Hall

2. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Chapter Contents Specifications for the ADT Dictionary  A Java Interface  Iterators Using the ADT Dictionary  A Directory of Telephone Numbers  The Frequency of Words  A Concordance of Words Java Class Library: the Interface Map

3. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Specifications for the ADT Dictionary 1 Contains entries that each have two parts  A key word or search key  A value associated with the key Fig. 17-1 An English dictionary.

4. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Specifications for the ADT Dictionary Fig. 17-2 An instance of an ADT dictionary has pairs of search keys and corresponding values

5. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Specifications for the ADT Dictionary 2 Data  Pairs of objects (key, value)  Number of pairs in the collection Operations add remove retrieve contains traverse keys traverse values isFull get number of entries remove all entries

6. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Specifications for the ADT Dictionary 3 Additional refinement possibilities  Distinct search keys vs.  Duplicate search keys  Secondary search keys View Java source code for interfacesource code

7. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Iterators 6 Note that getKeyIterator and getValueIterator return iterators  Create iterators for a dictionary dataBase with Possible to traverse  All search keys in dictionary without traversing values  All values without traversing search keys  All search keys and values in parallel

8. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Iterators Fig. 17-3 Two iterators that traverse a dictionary's keys and values in parallel.

9. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Using the ADT Dictionary 7 A directory of telephone numbers Fig 17-4 A class diagram for a telephone directory.

10. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X A Directory of Telephone Numbers Consider a client of the class TelephoneDirectory as specified in Fig. 17-4  View source codesource code  Note outputoutput View source code of class TelephoneDirectory class TelephoneDirectory

11. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X The Frequency of Words 12 We seek an ADT that will enable us to count each occurrence of a word as it is read from a text file View client program which uses FrequenceyCounterclient program  Note outputoutput View class FrequencyCounter used by the client FrequencyCounter

12. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X A Concordance of Words 18 Provide an index for finding a word in a file  Index would give the page number  A concordance would give the line number of a word (in a smaller file of words) A word may appear multiple times in the file  Appears once in index/concordance  The associated data is a list of page/line numbers View class ConcordanceConcordance

13. Carrano, Data Structures and Abstractions with Java, Second Edition, (c) 2007 Pearson Education, Inc. All rights reserved. 0-13-237045-X Java Class Library: The Interface Map 22 Package java.util contains interface Map  Similar to our ADT dictionary View list of method headerslist of method headers  Note similarity to methods developed in this chapter  Differences from our methods are highlighted