Demonstrate 演示 generic 通用、泛型
import java.util.EmptyStackException; import java.util.Stack; public class StackDemo { static void showpush(Stack<Integer> st,int a){ st.push(a); System.out.println("push(" + a +")"); System.out.println("Stack:" + st ); } static void showpop(Stack<Integer> st){ System.out.println("pop -> "); Integer a = st.pop(); System.out.println(a); System.out.println("Stack:" + st); } public static void main(String[] args) { Stack<Integer> st = new Stack<Integer>(); System.out.println("Stack:" + st); showpush(st,42); showpush(st, 66); showpush(st, 99); showpop(st); showpop(st); showpop(st); try { showpop(st); } catch (EmptyStackException e) { System.out.println("empty stack"); } /** * Stack:[] * push(42) * Stack:[42] * push(66) * Stack:[42, 66] * push(99) * Stack:[42, 66, 99] * pop -> * 99 * Stack:[42, 66] * pop -> * 66 * Stack:[42] * pop -> * 42 * Stack:[] * pop -> * empty stack */ } }