/** An Example of some array manipulation
**/
public class ArrayExample {
public static void main (String args[]) {
int numberOfElements = 0;
if (args.length > 0) {
// Use value from command line
numberOfElements = Integer.parseInt(args[0]);
}
ArrayExample anExample = new ArrayExample();
anExample.initializeArray(numberOfElements);
// Notice that method calls can be included in other method
// calls: in this case, returning primitive values that will
// be converted to String objects.
System.out.println("sum = " + anExample.Sum() +
" average = " + anExample.Average() );
}
private int[] intArray; // all instance (non static) methods
// have acess to this 'instance' variable
/** Initialize the array (which will be made big enough to hold
size entries) contents with some numbers */
public void initializeArray(int size) {
intArray = new int[size];
int startValue = size * 3; // pick any number
for (int i = 0; i < intArray.length; i++) {
intArray[i] = startValue; // put current number in next slot
startValue = startValue - 2; // and calculate next number
}
}
/** Calculate the sum of the array contents */
public long Sum() {
int index;
int arrayLen;
long sum = 0;
// All arrays have a length field that specifies how many
// elements the array contains
arrayLen = intArray.length;
// Calculate the sum the values in all array elements
for (index = 0; index < arrayLen; index++) {
sum += intArray[index];
}
return sum;
}
/** Calculate the average of the array contents */
public double Average() {
// Notice that Average calls Sum() to total the values in the
// array, rather than duplicating that calculation here. What
// is going on with the "(double)" ?
double average = (double) Sum() / intArray.length;
return average;
}
}
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