01969 PPT Ch09(Adv Arrays)

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Programming Logic andDesign

Fifth Edition, Comprehensive

Chapter 9Advanced Array Manipulation

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Programming Logic and Design, Fifth Edition, Comprehensive 2

Objectives

Learn about the need for sorting data

Swap two values in computer memory

Pass by value.vs. Pass by reference(address)

Understand the bubb le sor t Understand the insertion so rt

Understand the select ion so rt

Use mult id imensional arrays

Use a bu il t-inArrayclass

Use indexed fi les

Use a linked l ist

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Understanding the Need forSorting Records

Sequential order: records are arranged based onthe value in a field Examples: SSN, employee ID

Random order: records are in the order in whichthey were added

Sorting: placing the records in order, based on thevalues in one or more fields

Ascending order: arranged from lowest to highest Descending order: arranged from highest to lowest

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Understanding the Need forSorting Records (continued)

Median value: is the middle item when values arelisted in order

Mean value: is the arithmetic average

Computer always sorts based on numeric values Character data is sorted by its numeric code value

A is less than B

A has decimal value of 65, B is 66, C is 67, etc.

Lowercase a has decimal value of 97, b is 98,etc.

Whether A is greater than a is sys tem dependent(ASCII or EBCDIC or Unicode)

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Understanding How to SwapTwo Values

Swapping two values central to most sortingtechniques

When swapping two variables, you reversetheir

position Use a temporary variable named tempto hold onevalue.

publ ic static void swapScores (f loat [ ] scores)

{ f loat temp ;temp = scores[0];

scores[0] = scores[1];

scores[1] = temp; }

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How to Swap Two Array Values

publ ic stat ic vo id main(Str ing [ ] args ) {

f loat [ ] sco res = new float [3] ;

scores[0] = 91.5;

scores[1] = 84.8; scores[2] = 99.0;

swapSco res (scores [ ] );

}

pub l ic static void swapScores (f loat [ ] scores)

{ f loat temp;temp = scores[0];

scores[0] = scores[1];

scores[1] = temp; }


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Figure 9-1 Program segment that swaps two values

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Patrick Healy

Class #5 Arrays

Patrick Healy

Class #5 ArraysAlgorithms forSorting Arrays

n Some of the many algorithms that exist for sorting arrays are:

l Selection sortl Bubble sort Shell sort (similar to a bubble sort)

l Insertion sort

l Quick sort

l Merge sort

l Bucket sort

n These algorithms are typically studied in a data structures class,

but we will look at only the selection , insertion, and bubble sorts.

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Using a Bubble Sort

Bubble sort: one of the simplest sorting techniques

Items in a list compared in pairs

If an item is out of order, it swaps places with the

item below it In an ascendingsort, after a complete pass through

the list: Largest item sinks to the bottom

Smallest item bubbles to the top

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Figure 9-2 The SortScores program

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Figure 9-3 The fillArray()method

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Figure 9-4 The incomplete sortArray()method

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Figure 9-5 The swap() method

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Using a Bubble Sort (continued)

Start with x = 0, compare first pair and swapscore[0] = 90score[1] = 85

score[2] = 65

score[3] = 95

score[4] = 75

score[0] = 85

score[1] = 90

score[2] = 65

score[3] = 95

score[4] = 75

x = 1, compare with next and swap

score[0] = 85

score[1] = 90score[2] = 65

score[3] = 95

score[4] = 75

score[0] = 85

score[1] = 65score[2] = 90

score[3] = 95

score[4] = 75

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With x = 2, no swap neededscore[0] = 85score[1] = 65

score[2] = 90

score[3] = 95

score[4] = 75

score[0] = 85

score[1] = 65

score[2] = 90

score[3] = 95

score[4] = 75

x = 3, compare with x = 4 and swap

score[0] = 85

score[1] = 65score[2] = 90

score[3] = 95

score[4] = 75

score[0] = 85

score[1] = 65score[2] = 90

score[3] = 75

score[4] = 95

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Figure 9-6 The completed sortArray() method

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Use nested loops for sort ing an array

Inner loop m akes the pair compar ison s

Greatest number of compar isons is one less than

the number of array elements

Outer loop con tro ls the number of times to

process the list

One less than the number of array elements

Cl #5 ACl #5 A

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18Patrick Healy

Class #5 Arrays

Patrick Healy

Class #5 ArraysBubble Sort in Java

n Bubble sort: Sorts an array into ascending or descending order

and works by making several passes through the array.n During each pass, the smaller values rise and the larger values

sink.

n During each pass, successive elements of the array are

compared and swapped if necessary to ensure that the smallervalues rise and the larger values drop.

n At the end of the first pass, the largest value is guaranteed to

drop to the very bottom. And the smallest value rise by 1

position.

Cl #5 ACl #5 A

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ITP 120 Java Programming I19

Patrick Healy

Class #5 Arrays

Patrick Healy

Class #5 ArraysBubble Sort in Java

int [ ] array = {2, 9, 5, 4, 8 1 } // Length is 6

public static void bubbleSort( int [ ] array){

int temp; // Temporary hold item

for(int pass = 1; pass < array.length; pass++)

for (int j = 0; j < array.length 1; j++)

if (array[j] > array[j+1])

temp = array[j]; // swap the array elements

array [j] = array [j+1];

array [j+1] = temp;

}} // End of bubble sort method Click to see animation:

http://www.cs.oswego.edu/~mohammad/classes/csc241/samples/sort/Sort2-E.html
http://www.cs.oswego.edu/~mohammad/classes/csc241/samples/sort/Sort2-E.htmlhttp://www.cs.oswego.edu/~mohammad/classes/csc241/samples/sort/Sort2-E.htmlhttp://www.cs.oswego.edu/~mohammad/classes/csc241/samples/sort/Sort2-E.htmlhttp://www.cs.oswego.edu/~mohammad/classes/csc241/samples/sort/Sort2-E.htmlhttp://www.cs.oswego.edu/~mohammad/classes/csc241/samples/sort/Sort2-E.htmlhttp://www.cs.oswego.edu/~mohammad/classes/csc241/samples/sort/Sort2-E.html

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Liang, Introduction to Java Programming, Seventh Edition, (c) 2009 Pearson Education, Inc. Allrights reserved. 0136012671

20

Bubble Sort

2 5 9 4 8 1

2 5 4 9 8 1

2 5 4 8 9 1

2 5 4 8 1 9

(a) 1st pass

2 4 5 8 1 9

2 4 5 8 1 9

2 4 5 1 8 9

(b) 2nd pass

2 4 5 1 8 9

2 4 1 5 8 9

(c) 3rd pass

2 1 4 5 8 9

(d) 4th pass

2 9 5 4 8 1

(e) 5th pass

2 5 4 8 1 9 2 4 5 1 8 9 2 4 1 5 8 9 1 2 4 5 8 9

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Figure 9-6 The displayArray()method

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Sorting a List of Variable Size

Use a variable to ho ld the number of arrayelements

Declare the array w ith a large fixed s ize

Coun t the number of input elements

Store the coun t in variable

Use the variable to determ ine size of array

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Figure 9-8 Score sorting application in which number of elements to sort can vary

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Figure 9-8 Score sorting application in which number of elements to sort can vary(continued)

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Refining the Bubble Sort by ReducingUnnecessary Comparisons

After the first pass through the array:

Largest item must be at the end of array

Second largest item must be at the second-to-last

position in the array It is NOT necessary to compare those two values

again

On each subsequent pass through the array,

stop the pair comparisons one element sooner.

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Figure 9-9 Flowchart and pseudocode forsortArray()methodusing pairsToCompare variable

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Refining the Bubble Sort byEliminating Unnecessary Passes

Need one fewer pass than the number ofelements to completely sort the array

Can reduce the number of passes if array is

somewhat ordered already Use a flag variable to indicate if there were any

swaps during a single pass

If no swaps, the array is completely sorted

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Figure 9-10 Flow char t and ps eudocod e forsortArray()methodus ingswitchOccurred var iable

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Figure 9-10 Flow char t and ps eudocod e forsortArray()methodus ingswitchOccurredvar iable (cont inu ed)

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Using an Insertion Sort

Bubble sor tis one of the least eff icientsortingmethods

Insertion sort requires fewercomparisons

This sort compares a pair of elements If an element is smaller than the previous one, searchthe array backward from that point Insert this element at the proper location

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Insertion Sort in Javaint [ ] myList = {2, 9, 5, 4, 8, 1, 6}; // Unsorted

The insertion sortalgorithm sorts alist of values byrepeatedly insertingan unsorted elementinto a sorted sublistuntil the whole listis sorted.

2 9 5 4 8 1 6Step 1: Initially, the sorted sublist contains thefirst element in the list. Insert 9 to the sublist.

2 9 5 4 8 1 6Step2: The sorted sublist is {2, 9}. Insert 5 to the

sublist.

2 5 9 4 8 1 6Step 3: The sorted sublist is {2, 5, 9}. Insert 4 to

the sublist.

2 4 5 9 8 1 6Step 4: The sorted sublist is {2, 4, 5, 9}. Insert 8to the sublist.

2 4 5 8 9 1 6Step 5: The sorted sublist is {2, 4, 5, 8, 9}. Insert

1 to the sublist.

1 2 4 5 8 9 6Step 6: The sorted sublist is {1, 2, 4, 5, 8, 9}.Insert 6 to the sublist.

1 2 4 5 6 8 9Step 7: The entire list is now sorted

animation

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Insertion Sort in Java(Click the mouse to show the animation steps)

2 9 5 4 8 1 62 9 5 4 8 1 6

2 5 9 4 8 1 6

2 4 5 8 9 1 6

1 2 4 5 8 9 6

2 4 5 9 8 1 6

1 2 4 5 6 8 9

int [ ] myList = {2, 9, 5, 4, 8, 1, 6}; // Unsorted array

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Figure 9-12 Insertion sort

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Insertion Sort in Java

// InsertionSort.java Sort some numbers using Insertion sortpublic class InsertionSort {

public static void main (String [ ] args){// Initialize the listdouble[] myList = {5.0, 4.4, 1.9, 2.5, 3.4, 3.5, 89.7, 6.6, 75.2};

// Print the original listSystem.out.println("Array myList BEFORE Insertion Sort:\n");printList(myList);

insertionSort(myList); // Sort the list

// Print the sorted listSystem.out.println();System.out.println("Array myList AFTER Insertion Sort:\n");printList(myList);

} // End of main method

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Insertion Sort in Java (contd)

static void printList(double[ ] list) // Print numbers

{

for (int i=0; i

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Actual Insertion Sort Method in Java

// The Insertion Sort method for sorting the numberspublic static void insertionSort(double[ ] list) {

for (int i = 1; i < list.length; i++){double currentElement = list[i];

int k;for (k = i - 1; k >= 0 && list[k] > currentElement; k--)

{list[k+1] = list[k];

// Insert the current element into list[k+1]}list[k+1] = currentElement;

} // End of outer for loop

} // End of insertionSort method

} // End of class InsertionSort (started at top of main method)

Class #5 ArraysClass #5 Arrays

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Patrick Healy

Class #5 Arrays

Patrick Healy

Class #5 ArraysThe Selection Sort

n The selection sort algorithm that sorts a list in ascending order works as

follows:

l Find the largest item in the list and place it at the endl Remove the last item from further consideration, effectively reducing the list size

by 1

l Continue steps 1 and 2 until the list has only 1 item left to sort

n Consider this list of the integer numbers: 2 9 5 4 8 1 6

After 1st iteration 2 6 5 4 8 1 | 9

After 2nd iteration 2 6 5 4 1 | 8 9

After 3rd iteration 2 1 5 4 | 6 8 9

After 4th iteration 2 1 4 | 5 6 8 9After 5th iteration 2 1 | 4 5 6 8 9

After 6th iteration 1 | 2 4 5 6 8 9

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Using a Selection Sort

Selection sort: Sort two variables and s tore thesmallest value and its po si t ion in the array

Store f irst element value and its pos i t ion invariables

Compare it to the next element

If next element is smaller, pu t i ts value and pos it ionin th e variables

Con tinue un t i l end of array, at which t ime thesmallest value and its pos i t ion are in the variables

Swap the f irst element value and posi t ion w ith theelement and pos i t ion s tored in the variables

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Using a Selection Sort (continued)

Start at the second element in the array andrepeat the process

Con tinue un t i l al l elements except the last havebeen designated as the start ing poin t

After making one fewer pass than the number ofelements , the array is so rted

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Figure 9-13 A selection sort method

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Figure 9-13 A selection sort method (continued)


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Patrick Healy

Class #5 Arrays

Patrick Healy

Class #5 ArraysSelection Sort in Java

n public class SortBySelection { // A class SortBySelection

public static void selectionSorter( int [ ] list ) // A method in the class

{for ( int I = list.length 1; I >= 1; I --) {

int currentMax = list[0];

int currentMaxIndex = 0;

for (int j = 1; j

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Patrick Healy

y

Patrick Healy

ySelection Sort in Java

public static void main(String [ ] args ) {

int [ ] intArray = { 5, 15, 3, 21, 10, 16, 11};// print array before sortingSystem.out.println(Array before sorting: );printArray(int [ ] Array);selectionSorter(int [ ] Array); // Call selection sort

// print array after sortingSystem.out.println(Array after sorting: );printArray(int [ ] Array); // Print array values

}

public static void printArray(int [ ] array) {for (int k = 0; k < array.length; k++)System.out.println( + array[k]);

System.out.println(); }

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Using Multidimensional Arrays

One-dimensional (single-dimensional) array Represents a single list of values

Multidimensional array

A list with two or more related values in each position Two-dimensional array Represents values in a table or grid containing rows

and columns

Requires two subscripts

Three-dimensional array

Supported by many programming languages

Requires three subscripts

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Figure 9-14 View of a single-dim ension al array in m emory

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Table 9-1 Rent in $$ schedule based on floor and number of bedrooms

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2-Dimensional Table (5 rows x 3 columns)

oStudio Apt 1-Bedroom Apt 2- Bedroom Apt

(0,0) $350 (0,1) $390 (0,2) $435

(1,0) $400 (1,1) $440 (1,2) $480

(2,0) $475 (2,1) $530 (2,2) $575

(3,0) $600 (3,1) $650 (3,2) $700

(4,0) $1000 (4,1) $1075 (4,2) $1150


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Figure 9-15 Two-dimensionalrent array based o n rent sch edule in Table 9-1

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Figure 9-16 A program that determines rents


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Patrick HealyPatrick Healy

Copying Arrays in Java ( 3 ways to copy )

n Use a loop to copy individual array elements

for (int I = 0; I < sourceArray.length; I++)targetArray[ I ] = sourceArray[ I ];

n Use the clone method in the java.lang. Object class

int [ ] targetArray = (int [ ]) sourceArray.clone();

n Use the static arraycopy method in thejava.lang.System class

arraycopy(sourceArray, src pos, targetArray, tar pos, length);


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Copying Arrays using the arraycopy method

n Example:

int [ ] sourceArray = { 16, 24, 31, 45, 62}; // Declare ,create, initialize

int [ ] targetArray = new int[sourceArray.length]; // Same lengths

System.arraycopy(sourceArray, 0, targetArray,0,

sourceArray.length);

// Note: The zeros indicate the starting source & target positions


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Multidimensional ArraysDeclaring Variables of Multidimensional Arrays and Creating Multidimensional Arrays

int[][] matrix = new int[10][10];

or

int matrix[][] = new int[10][10];

matrix[0][0] = 3; // Insert the number 3 at position row 0,col 0

for (int i=0; i

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Multidimensional Array Illustrations

0 1 2 3 4

0

7

0 1 2 3 4

1

2

3

4

0

1

2

3

4

matrix[2][1] = 7;matrix = newint[5][5];

3

7

0 1 2

0

1

2

int[][] array = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9},

{10, 11, 12}

};

1 2 3

4 5 6

8 9

10 11 12


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Declaring, Creating, and Initializing Using Shorthand Notations

You can also use a shorthand notation to declare, create and

initialize a two-dimensional array. For example,Int [ ] [ ] array = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9},{10, 11, 12}

};

This is equivalent to the following statements:

int[ ] [ ] array = new int[4][3]; // 4 rows, 3 columns

array[0][0] = 1; array[0][1] = 2; array[0][2] = 3;





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ITP 120 Java Programming I55Patrick HealyPatrick Healy

Lengths of Multidimensional Arrays

int[ ][ ] array = {

{1, 2, 3},

{4, 5, 6},

{7, 8, 9},

{10, 11, 12}

};

array.length

array[0].length would be 3




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Ragged ArraysEach row in a two-dimensional array is itself an array. So,

the rows can have different lengths. Such an array isknown as a ragged array. For example,

int[ ][ ] matrix = {

{1, 2, 3, 4, 5},{2, 3, 4, 5},

{3, 4, 5},

{4, 5},

{5}

};


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Ragged Arrays Lengths of Ragged Arraysint[ ][ ] matrixArray = {

{1, 2, 3, 4, 5},

{2, 3, 4, 5},

{3, 4, 5},

{4, 5},

{5}

};

matrixArray[0].length is 5 matrixArray[4] .length is 1matrixArray[1].length is 4


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ITP 120 Java Programming I 58Patrick HealyPatrick Healy

Ragged Arrays: Creating Ragged ArraysIf you dont know the values in a ragged array in advance,

you can create a ragged array using the syntax whichfollows:

int[ ][ ] matrixArray = new int[5][ ];

matrixArray[0] = new int[5]; // Row of 5 integers

matrixArray[1] = new int[4];

matrixArray[2] = new int[3];matrixArray[3] = new int[2];

matrixArray[4] = new int[1]; // Row of one integer


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Ragged Arrays: Creating RaggedArrays

Now, you can assign random values to the array using thefollowing syntax:

for (int row = 0; row

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Multidimensional Arrays (N-Dimensional)

The general syntax for declaring an n-dimensional array is:

datatype [ ][ ][ ] arrayName = newdatatype[intSize1][intSize2][intSize3];

Where intSize1, intSize2, intSize3 are constant expressions yielding

positive integers.

Example: int [ ] [ ] [ ] myArray = new int [6][7][3];

The syntax to access a member of a n-dimensional array is:

arrayName[index1][index2][index3]

Class #5 ArraysClass #5 ArraysM lti Di i l A

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Multi-Dimensional Arrays

n 2-Dimensional Arrays are often used to represent tables or

matrices consisting of rows and colums of values.

n A table with 3 rows & 5 columns may be declared/created as

follows

int [ ][ ] twoDim = new int[3][5]; // rows first, columns second

Or

int twoDim[ ] [ ] = new int[3][5];

Or declare it first and create it later as in:

int twoDim[ ][ ];

twoDim = new int[3][5];


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n The table can also be created and initialized in one step as

follows:

int [ ][ ] twoDim = {

{ 2, 5, 6, 1, 12 },

{ 7, 9, 3, 5, 15 },

{ 21, 0, 7, 6, 3}

};The value at row 2, and column 4 is 5. Referred to as

twoDim[1][3]

What will be the value of val in the expression:int val = twoDim[2][4] + 16; // Answer is 3 + 16 = 19


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n Printing the twoDim table with nested for loops

for(int I = 0; I < 3; I++)for( j = 0; j < 5; j++)

System.out.print(twoDim[ i ][ j ] + );

System.out.println(); // Print a blank line

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Using a Built-In ARRAY Class

Similar tasks frequently performed on different arrays Example: filling and sorting

Modern programming languages provide an Arrayclass

Newer languages have vast libraries Contain built-in methods

Most useful Array class contains overloadedversions of each method call for each data type Different versions ofsort() methods for numeric and

string elements

If noArrayclass avai lable, w ri te your own

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Table 9-2 Typical useful methods of the Array class

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Using Indexed Files

Large data file to be accessed in sorted order; usuallyone field determines the sorting

Key field: field whose contents make the recordunique

Indexing records: a list of key fields is paired withcorresponding file position

Sorting indexes is fasterthan physically sortingactual records

Random-access storage device: records accessedin any order

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Table 9-3 Sample index

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Using Indexed Files (continued)

Address: location within computer memory or storage

Every data record on the disk has an address

Index: holds phys ical addresses and key f ield

values Data file is in some kind ofphysical order

While the Index is sorted in logical order

When a record is removed from an indexed file, the

index of the record is deleted from the index file

But the record is NOT physical ly removed

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Using Linked Lists

Linked list: requires one extra field in every record Holds the physical address of next logical record

Adding a new record:

Search the linked list for the correct logical location

Insert the new record Link the previous record to new record

Link the new record to next record in the list

Delete a record by unlinking it

More sophisticated linked lists store a next and aprevious field Can be traversed both forward and backward

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Table 9-4 Sample customerl inked l ist

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Table 9-5 Updated customerl inked l is t

Class #9 - Abstract Classes and Interfaces

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ITP 120 Java Programming I 72Patrick Healy

Linked Lists in JavaArrays are useful for storing and managing a set of

elements of the same type. However, since the length ofan array is fixed once the array is created, you need toknow the length of the array before you create it. Alinked list can grow or shrink dynamically as needed.

(like a vector in the Vector class in Java)

A linked list consists of nodes Each node contains anelement and each node is linked to its next neighbor.

Thus, a node can be defined as a class as follows:


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The Linked List Structurepublic class Node

{ Object element;

Node next; // Points to next node

public Node(Object o)

{ element = o; } // Constructor}

first element

next

element

next

element

next

last

node1 node2 node n


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The Linked List StructureBelow, the variable f i rstrefers to the first node in the

list, and the variable lastrefers to the last node in thelist. If the list is empty, both are nul l(null addresses)

first element

next

element

next

element

next

last

node1 node2 node n

Class #9 - Abstract Classes and InterfacesLinked Lists: Example for 3 Circle objects

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Linked Lists: Example for 3 Circle objects

Create 3 nodes to store 3 circle objects with radii of 1, 2, and 3 in a

linked list:

Node first; // Declare first node

Node last; // Declare last node

// Create a node to store the 1st circle object

first = new Node(new Circle (1.0));

last = first; // The last node will point to 1st node

last.next = new Node ( new Circle (2)); // Node for 2nd circle object

last = last.next; // Last node is now Circle (2) objectlast.next = new Node ( new Circle (3)); // Node for 3rd circle object

last = last.next; // Last node is now Circle (3) object


Create a Linked List with three Nodes

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Create a Linked List with three Nodes(objects)

Node n1 = new Node(new String(Welcome to Java!));Node n2 = new Node(new JButton(OK));

Node n3 = new Node(new JButton(Cancel));

n1.next = n2; // Link to node n2n2.next = n3; // link to node n3

Node first = n1; // Set first node

Node last = n3; // Set last node


G i Li k d Li t Add N d

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Generic Linked Lists: Add a Node

element

next

element

next

current

first element

next

element

next:null

last

element

next

New node inserted here

temp

To add a new node


Generic Linked Lists: Remove a Node

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Generic Linked Lists: Remove a Node

Remove a new node

element

next

element

next

previous

first element

next

element

next:null

last

Node to be deleted

current

After the node isdeleted

Class #9 - Abstract Classes and InterfacesSample Program: TestLinked List.java

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Sample Program: TestLinked List.java

public class TestLinkedList {

public static void main(String[ ] args) {

// Create a linked list

GenericLinkedList list = new GenericLinkedList();

// Add elements to the list

list.addFirst(Jason"); // Becomes index 2

list.addFirst(Carol"); // Becomes index 1

list.addLast(James"); // Becomes last_index - 1

list.addLast(Daniel"); // Becomes last_index

list.add("Mary", 2); // Becomes index 3

list.add("Susan", 5); // Becomes index 7

list.add("Chris", 0); // Becomes first index

Class #9 - Abstract Classes and InterfacesTestLinked List.java

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TestLinked List.java

// Print the list

System.out.println("Strings are added to the linked list are:");

list.printList();

System.out.println();

// Remove elements from the list

list.remove("Chris"); // Remove "Chris"

list.remove(2); // Remove Jason"list.removeLast( ); // Remove "Susan"

// Print the list

System.out.println("The contents of linked list after deletions:");

list.printList();

}

}

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Chapter 9 Summary

Sort data reco rds based on the contents of one ormore f ie lds

Ascending o rder

Descending order

Swap two values

Tempo rary variable holds one of the values

Bubble sor t

Compares pairs

Swaps w ith i tem below

Ascending bubble sor t : largest i tem sinks to bot tom

Smal lest i tem r ises o r bubbles to the top

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Chapter 9 Summary (continued)

Bubble sor t(continued) Eliminate unnecessary compar ison s in each pass and

eliminate unnecessary passes to improve bubble sor t

Size of l ist to be sorted may vary

Coun t values to be sorted In i t ia lize array with c oun t var iable when value is known

Bub ble sor t impro ved by stopping c ompar isons one element

soon er on each pass

Bub ble sor t imp roved by stop ping when al l items sor ted

Flag var iable indicates when any item is swapped

Ind icates when no i tems sw apped in on e pass throu gh

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Insert ion so rtusually requires fewercomparisons

Pair-wise compar isons are done.

Locate the out-of-ord er element

Search array backward to a smaller element Move each element down one

Insert out-of-order element into open posi t ion

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Ascending o rder select ion so rt

First element assumed to be smallest

Value and posit ion s tored in variables

Every subsequent element tested Smallest element found , value and pos it ion

saved

Lowest value in f i rst posi t ion after one pass

through array

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One-dimensional array

Also called single-dimensional array

Single column of values

Accessed with a sing le subscr ip t Most object-oriented languages support two-

dimensional arrays and more

Both rows and columns

Two subscripts

End of Chapter 9

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End of Chapter 9Summary

Arrayclasscontains useful methods formanipulating arrays

Ind exed fi lesaccess data records in a logicalorder

Differs from physical order

Must identify key fieldfor each record

A l inked l istcontains extra field within every

record the extra f ield ho lds phys ical address of next

logical record

01969 PPT Ch09(Adv Arrays)

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