Arrays - Java Software Solutions: Foundations of Program Design - page 380

8.1 Array Elements

An array is a simple but powerful programming language construct used to
group and organize data. When writing a program that manages a large amount
of information, such as a list of 100 names, it is not practical to declare separate
variables for each piece of data. Arrays solve this problem by letting us declare
one variable that can hold multiple, individually accessible values.
An array is a list of values. Each value is stored at a specific, numbered position
in the array. The number corresponding to each position is called an index or a
subscript. Figure 8.1 shows an array of integers and the indexes that correspond
to each position. The array is called height ; it contains integers that represent
several peoples' heights in inches.
In Java, array indexes always begin at zero. Therefore the value stored at index
5 is actually the sixth value in the array. The array shown in Figure 8.1 has 11
values, indexed from 0 to 10.
To access a value in an array, we use the name of the array fol-
lowed by the index in square brackets. For example, the following
expression refers to the ninth value in the array height :

KEY CONCEPT
An array of size N is indexed from
0 to N-1.

height[8]

According to Figure 8.1, height[8] (pronounced height-sub-eight) contains
the value 79. Don't confuse the value of the index, in this case 8, with the value
stored in the array at that index, in this case 79.

height

0 69

1
2
3

61
70

index

74
62
69

4
5 value of height[5]

6
7

66
73

8
9
10

79
62

70

FIGURE 8.1 An array called height containing integer values