Java Reference
In-Depth Information
public class ArrayDemo
{
public static void main(String [] args)
{
int [] sums;
sums = new int[20];
sums[0] = 1;
for(int i = 1; i < 20; i++)
{
sums[i] = sums[i-1] + i;
}
for(int i = 0; i < sums.length; i++)
{
System.out.println(“sums[“ + i + “] = “ + sums[i]);
}
System.out.println(sums.toString());
double [] temps = new double[31];
temps[0] = 85.0;
temps[1] = 79.5;
temps[2] = 76.0;
Employee [] myCompany;
myCompany = new Employee[500];
myCompany[227] = new Employee(“George Washington”,
“Mount Vernon”, 1);
myCompany[227].mailCheck();
System.out.println(“The length of myCompany is “
+ myCompany.length);
System.out.println(temps[31]);
}
}
I want to make a few observations about the ArrayDemo program:
Because arrays are objects, their class types extend java.lang.Object.
This means that you can invoke any of the Object methods on arrays. In
ArrayDemo, the toString() method is invoked on the sums array.
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The statement “Constructing an Employee” prints out only once, mean-
ing that only one Employee object is created in memory.
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The final statement in main() accesses temps[31], which compiles but
causes an ArrayIndexOutOfBoundsException, as shown in the output
in Figure 9.1.
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