Stack(栈)的使用

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"));

        System.out.println(stack.pop());

        System.out.println(stack.pop()); 

        System.out.println(stack.pop());

        System.out.println(stack.pop()); 

       

    } 

    public static String isEmpty(Stack<String> stack) { 

        return stack.empty() ? "empty" : "not empty"; 

    }

now the stack is empty

now the stack is not empty

5

5

4

2

3

2

1

Exception in thread "main" java.util.EmptyStackException

         at java.util.Stack.peek(Unknown Source)

         at java.util.Stack.pop(Unknown Source)

         at com.main.StackClass.main(StackClass.java:22)