Java Stack isEmpty()用法及代码示例

Java中的Java.util.Stack.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。

用法:

Stack.isEmpty()

参数：此方法不带任何参数。

返回值：如果Stackis为空，则此函数返回True，否则返回False。

以下示例程序旨在说明Java.util.Stack.isEmpty()方法：

示例1:

// Java code to illustrate isEmpty() 
import java.util.*; 
  
public class StackDemo { 
    public static void main(String args[]) 
    { 
        // Creating an empty Stack 
        Stack<String> stack = new Stack<String>(); 
  
        // 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

示例2:

// Java code to illustrate isEmpty() 
import java.util.*; 
  
public class StackDemo { 
    public static void main(String args[]) 
    { 
        // Creating an empty Stack 
        Stack<Integer> stack = new Stack<Integer>(); 
  
        // 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

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注：本文由纯净天空筛选整理自Code_r大神的英文原创作品 Stack isEmpty() method in Java with Example。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。