[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";  
        }  
    }