ARRAYS - Java Programming: From Problem Analysis to Program Design - page 560

Example 9-3 further illustrates how to process one-dimensional arrays.
EXAMPLE 9-3
This example shows how loops are used to process arrays. The following declaration is
used throughout this example:
double [] sales = new double [10];
double largestSale, sum, average;
The first statement creates the array sales of 10 elements, with each element of type
double . The meaning of the other statements is clear. Also, notice that the value of
sales.length is 10 .
Loops can be used to process arrays in several ways:
1. Initializing an array to a specific value: Suppose that you want to initialize
every element of the array sales to 10.00 . You can use the following loop:
for ( int index = 0; index < sales.length; index++)
sales[index] = 10.00;
2. Reading data into an array: The following loop inputs data into the
array sales . For simplicity, we assume that the data is entered at the
keyboard one number per line.
for ( int index = 0; index < sales.length; index++)
sales[index] = console.nextDouble();
3. Printing an array: The following loop outputs the elements of array
sales . For simplicity, we assume that the output goes to the screen.
for ( int index = 0; index < sales.length; index++)
System.out.print(sales[index] + " ");
4. Finding the sum and average of an array: Because the array sales ,
as its name implies, represents certain sales data, it may be desirable to
find the total sale and average sale amounts. The following Java code
finds the sum of the elements of the array sales (total sales) and the
average sale amount:
sum = 0;
for ( int index = 0; index < sales.length; index++)
sum = sum + sales[index];
if (sales.length != 0)
average = sum / sales.length;
else
average = 0.0;