/*
    TestGenerics6.java
    CIS 260
    David Klick
    1/28/2010
    
    This program demonstrates using the ? wildcard in Java generics.
    This is basically the same as a program presented in the text
    for the course.
*/
import java.util.Arrays;
import java.util.ArrayList;

public class TestGenerics6 {
    public static void main(String[] args) {
        Integer[] inums = { 2, 4, 6, 8, 10 };
        ArrayList<Integer> iarray = new ArrayList<Integer>(Arrays.asList(inums));
        Double[] dnums = { 8.2, 3.7, 6.3, 2.8, 9.2 };
        ArrayList<Double> darray = new ArrayList<Double>(Arrays.asList(dnums));
        System.out.printf("Sum: %.2f\n", sum(iarray));
        System.out.printf("Sum: %.2f\n", sum(darray));
    }
    
    private static double sum(ArrayList<? extends Number> a) {
        double sum = 0.0;
        for (Number n : a) sum += n.doubleValue();
        return sum;
    }
}