Java TreeSet descendingIterator()用法及代码示例

java.util.TreeSet类的descendingIterator()方法用于按降序返回对此集合中的元素的迭代器。

用法:

public Iterator descendingIterator()

返回值：此方法以降序返回此集合中元素的迭代器。

以下示例说明了descendingIterator()方法

示例1:

// Java program to demonstrate 
// descendingIterator() method 
// for Integer value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // create tree set object 
            TreeSet<Integer> treeadd = new TreeSet<Integer>(); 
  
            // populate the TreeSet using add() method 
            treeadd.add(10); 
            treeadd.add(20); 
            treeadd.add(30); 
            treeadd.add(40); 
  
            // Print the TreeSet 
            System.out.println("TreeSet: " + treeadd); 
  
            // create descending iterator 
            // using descendingIterator() method 
            Iterator<Integer> 
                iterator = treeadd.descendingIterator(); 
  
            System.out.println("\nValues using DescendingIterator:"); 
  
            // printing the interated value 
            while (iterator.hasNext()) { 
                System.out.println("Value : "
                                   + iterator.next()); 
            } 
        } 
  
        catch (NullPointerException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

TreeSet: [10, 20, 30, 40]

Values using DescendingIterator:
Value : 40
Value : 30
Value : 20
Value : 10

示例2:

// Java program to demonstrate 
// descendingIterator() method 
// for String value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // create tree set object 
            TreeSet<String> treeadd = new TreeSet<String>(); 
  
            // populate the TreeSet using add() method 
            treeadd.add("A"); 
            treeadd.add("B"); 
            treeadd.add("C"); 
            treeadd.add("D"); 
  
            // Print the TreeSet 
            System.out.println("TreeSet: " + treeadd); 
  
            // create descending iterator 
            // using descendingIterator() method 
            Iterator<String> 
                iterator = treeadd.descendingIterator(); 
  
            System.out.println("\nValues using DescendingIterator:"); 
  
            // printing the interated value 
            while (iterator.hasNext()) { 
                System.out.println("Value : "
                                   + iterator.next()); 
            } 
        } 
  
        catch (Exception e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

TreeSet: [A, B, C, D]

Values using DescendingIterator:
Value : D
Value : C
Value : B
Value : A

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 TreeSet descendingIterator() method in Java with Examples。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。