Chapter 10: Class Vector and String, and Enumeration Types Java Programming: Program Design Including Data Structures Program Design Including Data Structures

Java Programming: Program Design Including Data Structures2 Chapter Objectives  Learn how to implement the sequential search algorithm  Explore how to sort an array using bubble sort, selection sort, and insertion sort algorithms  Learn how to implement the binary search algorithm  Become aware of the class Vector  Learn more about manipulating strings using the class String

Java Programming: Program Design Including Data Structures3 List Processing  List: A set of values of the same type  Basic operations performed on a list:  Search list for given item  Sort list  Insert item in list  Delete item from list

Java Programming: Program Design Including Data Structures4 Search  Necessary components to search a list:  Array containing the list  Length of the list  Item for which you are searching  After search completed:  If item found, report “success” and return location in array  If item not found, report “failure”

Java Programming: Program Design Including Data Structures5 Search (continued) public static int seqSearch(int[] list, int listLength, int searchItem) { int loc; boolean found = false; for (loc = 0; loc < listLength; loc++) if (list[loc] == searchItem) { found = true; break; } if (found) return loc; else return -1; }

Java Programming: Program Design Including Data Structures6 Bubble Sort  Suppose list[0...n - 1] is a list of n elements  We want to rearrange (sort) the elements of list  The bubble sort algorithm works as follows:  In a series of n - 1 iterations, the successive elements, list[index] and list[index + 1], of list are compared  If list[index] is greater than list[index + 1], then the elements list[index] and list[index + 1] are swapped (interchanged)

Java Programming: Program Design Including Data Structures7 Bubble Sort

Java Programming: Program Design Including Data Structures8 Bubble Sort (continued)

Java Programming: Program Design Including Data Structures9 public static void bubbleSort(int list[], int listLength) { int temp; int counter, index; for (counter = 0; counter < listLength - 1; counter++) { for (index = 0; index < listLength - 1 – counter; index++) if (list[index] > list[index + 1]) { temp = list[index]; list[index] = list[index + 1]; list[index + 1] = temp; } Bubble Sort (continued)

Java Programming: Program Design Including Data Structures10 Selection Sort  List is sorted by selecting list element and moving it to its proper position  Algorithm finds position of smallest element and moves it to top of unsorted portion of list  Repeats process above until entire list is sorted

Java Programming: Program Design Including Data Structures11 Selection Sort (continued)

Java Programming: Program Design Including Data Structures12 Selection Sort (continued)

Java Programming: Program Design Including Data Structures13 public static void selectionSort(int[] list, int listLength) { int index; int smallestIndex; int minIndex; int temp; for (index = 0; index < listLength – 1; index++) { smallestIndex = index; for (minIndex = index + 1; minIndex < listLength; minIndex++) if (list[minIndex] < list[smallestIndex]) smallestIndex = minIndex; temp = list[smallestIndex]; list[smallestIndex] = list[index]; list[index] = temp; } Selection Sort (continued)

Java Programming: Program Design Including Data Structures14 Insertion Sort The insertion sort algorithm sorts the list by moving each element to its proper place

Java Programming: Program Design Including Data Structures15 Insertion Sort (continued)

Java Programming: Program Design Including Data Structures16 Insertion Sort (continued)

Java Programming: Program Design Including Data Structures17 Insertion Sort (continued)

Java Programming: Program Design Including Data Structures18 public static void insertionSort(int[] list,int noOfElements) { int firstOutOfOrder, location; int temp; for (firstOutOfOrder = 1; firstOutOfOrder < noOfElements; firstOutOfOrder++) { if (list[firstOutOfOrder] < list[firstOutOfOrder - 1]) { temp = list[firstOutOfOrder]; location = firstOutOfOrder; do { list[location] = list[location - 1]; location--; } while(location > 0 && list[location - 1] > temp); list[location] = temp; } } //end insertionSort Insertion Sort (continued)

Java Programming: Program Design Including Data Structures19 Sequential Ordered Search public static int seqOrderedSearch(int[] list, int listLength, int searchItem) { int loc; //Line 1 boolean found = false; //Line 2 for (loc = 0; loc < listLength; loc++) { //Line 3 if (list[loc] >= searchItem) { //Line 4 found = true; //Line 5 break; //Line 6 } if (found) //Line 7 if (list[loc] == searchItem) //Line 8 return loc; //Line 9 else //Line 10 return -1; //Line 11 else //Line 12 return -1; //Line 13 } // In Line 11, return –(loc+1);

Java Programming: Program Design Including Data Structures20 Binary Search Algorithm  Search item is compared with middle element of list  If search item < middle element of list, search is restricted to first half of the list  If search item > middle element of list, search is restricted to second half of the list  If search item = middle element, search is complete

Java Programming: Program Design Including Data Structures21 Binary Search Algorithm Determine whether 75 is in the list.

Java Programming: Program Design Including Data Structures22 public static int binarySearch(int[] list, int listLength, int searchItem) { int first = 0; int last = listLength - 1; int mid; boolean found = false; while (first <= last && !found) { mid = (first + last) / 2; if (list[mid] == searchItem) found = true; else if (list[mid] > searchItem) last = mid - 1; else first = mid + 1; } if (found) return mid; else return –1; } //end binarySearch Binary Search Algorithm

Java Programming: Program Design Including Data Structures23 Vectors  The class Vector can be used to implement a list  Unlike an array, the size of a Vector object can grow/shrink during program execution  You do not need to worry about the number of data elements in a vector

Java Programming: Program Design Including Data Structures24 Members of the class Vector

Java Programming: Program Design Including Data Structures25 Members of the class Vector (continued)

Java Programming: Program Design Including Data Structures26 Members of the class Vector (continued)

Java Programming: Program Design Including Data Structures27 Members of the class Vector (continued)

Java Programming: Program Design Including Data Structures28 Vectors (continued)  Every element of a Vector object is a reference variable of the type Object  To add an element into a Vector object:  Create appropriate object  Store data into object  Store address of object holding data into Vector object element

Java Programming: Program Design Including Data Structures29 Vector stringList = new Vector (); stringList.addElement("Spring"); stringList.addElement("Summer"); stringList.addElement("Fall"); stringList.addElement("Winter"); Vectors (continued)

Java Programming: Program Design Including Data Structures30 String  The class String is a very important class in Java.  Additional String methods are discussed.

Java Programming: Program Design Including Data Structures31 Additional String Methods

Java Programming: Program Design Including Data Structures32 Additional String Methods (continued)

Java Programming: Program Design Including Data Structures33 Additional String Methods (continued)

Java Programming: Program Design Including Data Structures34 Additional String Methods (continued)

Executing String Methods  Consider the following statements: String sentence; String str1; String str2; String str3; String str4; sentence = “It is sunny and warm.”; str1 = “warm.”; str2 = “Programming with Java”; str3 = “sunny”; str4 = “Learning Java Programming is exciting”; Java Programming: Program Design Including Data Structures35

Java Programming: Program Design Including Data Structures36 Effects of Some String Methods

Java Programming: Program Design Including Data Structures37 Enumeration Types  Java allows programmers to create their own data types by specifying the values of that data type.  The values belonging to primitive data types are predefined.  enumeration of enum types using the key word enum  The values of the enum data type are identifiers.  Used as a public static reference variables to objects of the enum type enum Grades {A, B, C, D, F}; where A, B, …, F are enum constants (unique values) Grades an enum type Grades myGrade; myGrade = Grades.B;

Java Programming: Program Design Including Data Structures38 Enumeration Methods  Methods in enumeration of enum types  ordinal() returns the ordinal value of an enum constant  name() returns the name of the enum value  values() returns the values of an enum type as a list

Java Programming: Program Design Including Data Structures39 Chapter Summary  Lists  Searching lists:  Sequential searching  Sequential searching on an order list  Binary search  Sorting lists:  Bubble sort  Selection sort  Insertion sort

Java Programming: Program Design Including Data Structures40 Chapter Summary (continued)  Programming examples  The class Vector  Members of the class Vector  The class String  Additional methods of the class String  Enumeration enum Types  Members of the class Vector