[Java]Stack类

Java Stack类顾名思义，实现堆栈。具体方法如下：

    import java.util.Stack;  

    public class StackTest {  

        public static void main(String[] args) {
            Stack<String> stack = new Stack<String>();
            System.out.println("now the stack is " + isEmpty(stack));
            stack.push("1");
            stack.push("2");
            stack.push("3");
            stack.push("4");
            stack.push("5");
            System.out.println("now the stack is " + isEmpty(stack));
            System.out.println(stack.peek());
            System.out.println(stack.pop());
            System.out.println(stack.pop());
            System.out.println(stack.search("2"));
        }
        public static String isEmpty(Stack<String> stack) {
            return stack.empty() ? "empty" : "not empty";
        }
    }