在Java中使用示例堆栈 isEmpty() 方法

Java 中的Java Java .isEmpty() 方法用于检查和验证 Stack 是否为空。如果堆栈为空，则返回 True，否则返回 False。

句法：

Stack.isEmpty()

参数：此方法不带任何参数。

返回值：如果 Stack 为空，则此函数返回True ，否则返回False 。

下面的程序说明了Java.util.Stack.isEmpty() 方法：

方案一：

// Java code to illustrate isEmpty()
import java.util.*;
  
public class StackDemo {
    public static void main(String args[])
    {
        // Creating an empty Stack
        Stack stack = new Stack();
  
        // Use add() method to add elements into the Stack
        stack.add("Welcome");
        stack.add("To");
        stack.add("Geeks");
        stack.add("4");
        stack.add("Geeks");
  
        // Displaying the Stack
        System.out.println("Stack:  " + stack);
  
        // Verifying if the Stack is empty or not
        System.out.println("Is the Stack empty? "
                           + stack.isEmpty());
  
        // Clearing the Stack
        stack.clear();
  
        // Displaying the Stack
        System.out.println("Stack after clear(): "
                           + stack);
  
        // Verifying if the Stack is empty or not
        System.out.println("Is the Stack empty? "
                           + stack.isEmpty());
    }
}

输出：

Stack:  [Welcome, To, Geeks, 4, Geeks]
Is the Stack empty? false
Stack after clear(): []
Is the Stack empty? true

方案二：

// Java code to illustrate isEmpty()
import java.util.*;
  
public class StackDemo {
    public static void main(String args[])
    {
        // Creating an empty Stack
        Stack stack = new Stack();
  
        // Displaying the Stack
        System.out.println("Stack:  " + stack);
  
        // Verifying if the Stack is empty or not
        System.out.println("Is the Stack empty? "
                           + stack.isEmpty());
    }
}

输出：

Stack:  []
Is the Stack empty? true