Chapter 7 Arrays

An array is a systematic arrangement of objects, usually in rows and columns. Specifically, it may refer to:Generally, a collection of data items that can be selected by indices computed at run-time, including: Array data structure, an arrangement of items at equally spaced addresses in computer memory | Chapter 7 Arrays © 2004 Pearson Addison-Wesley. All rights reserved 7- Arrays Arrays are objects that help us organize large amounts of information Chapter 7 focuses on: array declaration and use bounds checking and capacity arrays that store object references variable length parameter lists multidimensional arrays the ArrayList class © 2004 Pearson Addison-Wesley. All rights reserved 7- Outline Declaring and Using Arrays Arrays of Objects Variable Length Parameter Lists Two-Dimensional Arrays The ArrayList Class Polygons and Polylines © 2004 Pearson Addison-Wesley. All rights reserved 7- Arrays An array is an ordered list of values 0 1 2 3 4 5 6 7 8 9 79 87 94 82 67 98 87 81 74 91 An array of size N is indexed from zero to N-1 scores The entire array has a single name Each value has a numeric index This array holds 10 values that are indexed from 0 to 9 © 2004 Pearson Addison-Wesley. All rights reserved 7- Arrays A particular value in an array is referenced using the | Chapter 7 Arrays © 2004 Pearson Addison-Wesley. All rights reserved 7- Arrays Arrays are objects that help us organize large amounts of information Chapter 7 focuses on: array declaration and use bounds checking and capacity arrays that store object references variable length parameter lists multidimensional arrays the ArrayList class © 2004 Pearson Addison-Wesley. All rights reserved 7- Outline Declaring and Using Arrays Arrays of Objects Variable Length Parameter Lists Two-Dimensional Arrays The ArrayList Class Polygons and Polylines © 2004 Pearson Addison-Wesley. All rights reserved 7- Arrays An array is an ordered list of values 0 1 2 3 4 5 6 7 8 9 79 87 94 82 67 98 87 81 74 91 An array of size N is indexed from zero to N-1 scores The entire array has a single name Each value has a numeric index This array holds 10 values that are indexed from 0 to 9 © 2004 Pearson Addison-Wesley. All rights reserved 7- Arrays A particular value in an array is referenced using the array name followed by the index in brackets For example, the expression scores[2] refers to the value 94 (the 3rd value in the array) That expression represents a place to store a single integer and can be used wherever an integer variable can be used © 2004 Pearson Addison-Wesley. All rights reserved 7- Arrays For example, an array element can be assigned a value, printed, or used in a calculation: scores[2] = 89; scores[first] = scores[first] + 2; mean = (scores[0] + scores[1])/2; ("Top = " + scores[5]); © 2004 Pearson Addison-Wesley. All rights reserved 7- Arrays The values held in an array are called array elements An array stores multiple values of the same type – the element type The element type can be a primitive type or an object reference Therefore, we can create an array of integers, an array of characters, an array of String objects, an array of Coin objects, etc. In Java, the array itself is an object that must be instantiated © 2004 Pearson .