gs gs128 Java Generics - Java Wildcards - Quiz No.1

 import java.util.*; class Output { public static double sumOfList(List<? extends Number> list) { double s = 0.0; for (Number n : list) s += n.doubleValue(); return s; } public static void main(String args[]) { List<Integer> li = Arrays.asList(1, 2, 3); System.out.println(sumOfList(li)); } }

 import java.util.*; class Output { public static double sumOfList(List<? extends Number> list) { double s = 0.0; for (Number n : list) s += n.doubleValue(); return s; } public static void main(String args[]) { List<Double> ld = Arrays.asList(1.2, 2.3, 3.5); System.out.println(sumOfList(ld)); } }

 import java.util.*; public class genericstack <E> { Stack <E> stk = new Stack <E>(); public void push(E obj) { stk.push(obj); } public E pop() { E obj = stk.pop(); return obj; } } class Output { public static void main(String args[]) { genericstack <Integer> gs = new genericstack<Integer>(); gs.push(36); System.out.println(gs.pop()); } }