Getting to Know Java - Beginning Java Programming: The Object-Oriented Approach - page 35

The array can then be initialized using the new operator, as follows:

weightArray = new float[5];

weightArray

The array now has space to store five floating numbers—the first num-
ber is stored at index position 0 and the last number is stored at index
position 4. The values stored initially will be the default values for the
data type, which is 0.0 for float. Figure 2-11 gives a visual representa-
tion of the array in this initialized state.

0 1 2 3 4

index

figure 2-11

You can now populate the array as follows:

weightArray[0] = 85f;
weightArray[1] = 72f;
weightArray[2] = 68f;
weightArray[3] = 94f;
weightArray[4] = 78f;

weightArray

Remember the letter f is added at the end of each of the numbers to
indicate that they are floating point numbers. The weightArray popu-
lated with the specified floats is visualized in Figure 2-12.

85 72 68 94 78

0 1 2 3 4

index

Initializing and populating the array can both be done more concisely,
as follows:

figure 2-12

float[] weightArray = {85f, 72f, 68f, 94f, 78f};

This way, the data type is given, the array is indicated with the square brackets ( [] ), the name is given
as weightArray , and the size is set based on the number of elements given between the brackets ( {} ).

The following Java program illustrates how arrays can be used to calculate the BMI for a set of five
people.

public class BMIcalculator {

// This is our main method.
public static void main(String[] args){

// initialize the three arrays as each having 5 elements

float[] weightArray = new float[5];
float[] heightArray = new float[5];
float[] BMIArray = new float[5];

// assign the values to the weight array
weightArray[0] = 85f;
weightArray[1] = 72f;
weightArray[2] = 68f;
weightArray[3] = 94f;
weightArray[4] = 78f;

//assign the values to the height array
heightArray[0] = 1.74f;