Assignment #20 CS360

Assignment #20
"Wildcard Test"
12-02-10




//WildcardTest.java

//Wildcard test program.

import java.util.ArrayList;

public class WildcardTest

{
public static void main( String[] args )

{
//create, initialize and output ArrayList of integers, then
//display total of the elements

Integer[] integers = { 1, 2, 3, 4, 5 };

ArrayList integerList = new ArrayList ();

//insert elements in intergerList
for( Integer element : integers )
integerList.add( element );

System.out.printf( "integerList contains: %s\n", integerList );
System.out.printf( "Total of the elements in integerList: %.0f\n\n",
sum( integerList ) );

//create, initialize and output ArrayList of Doubles, then
//display total of the elements
Double[] doubles = {1.1, 3.3, 5.5 };
ArrayList< Double > doubleList = new ArrayList< Double >();

//Insert Elements in doubleList
for( Double element : doubles )
doubleList.add( element );

System.out.printf( "doubleList contains:%s\n", doubleList );
System.out.printf( "Total of the elements in doubleList: %.1f\n\n",
sum( doubleList ));

//create, initialize and output ArrayList of Numbers containing
//both Integers and Doubles, then display total of the elements
Number[] numbers = {1, 2.4, 3, 4.1 }; //Integers and Doubles
ArrayList< Number > numberList = new ArrayList< Number >();

//Insert elements in numberList
for( Number element : numbers )
numberList.add( element );

System.out.printf( "numberList contains: %s\n", numberList );
System.out.printf( "Total of the elements in numberList: %.1f\n",
sum( numberList));

}//end main

//total the elements; using a wildcard in the ArrayList parameter
public static double sum( ArrayList< ? extends Number > list )
{
double total = 0; //initialize total

//calculate sum
for( Number element : list )
total += element.doubleValue();

return total;

}//end method sum
}//end class WildcardTest