java編程思想 ListIterator 逆序

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 1 package net.bigwrok; 2  3 import java.util.ArrayList; 4 import java.util.Arrays; 5 import java.util.LinkedList; 6 import java.util.List; 7 import java.util.ListIterator; 8  9 public class CopyTest {10     static void reverse(List<Integer> list) {11         ListIterator<Integer> fwd = list.listIterator();12         ListIterator<Integer> rev = list.listIterator(list.size());13         int mid = list.size() / 2;// list.size() >> 1;14         for (int i = 0; i < mid; i++) {15             Integer tmp = fwd.next();16             fwd.set(rev.previous());17             rev.set(tmp);18         }19     }20     static void reverse2(List<Integer> list) {21         //僅僅輸出  it.previous() ，第一次輸出的元素index是 (size11 -1)22          int size11  =  list.size();23         ListIterator<Integer> it = list.listIterator(size11);24         while (it.hasPrevious()) {25             System.out.print (it.previous()+" , ");26         }27         System.out.println(); 28     }29 30     public static void main(String[] args) {31         List<Integer> src = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9);32         List<Integer> dest = new LinkedList<Integer>(src);33          34         System.out.println("source: " + src);35         System.out.println("destination: " + dest);36         37         reverse(dest);38         //reverse2(dest);39         System.out.println("source: " + src);40         System.out.println("destination: " + dest);41         42          43     44     }45 46 }

 

結果

1 source: [1, 2, 3, 4, 5, 6, 7, 8, 9]2 destination: [1, 2, 3, 4, 5, 6, 7, 8, 9]3 source: [1, 2, 3, 4, 5, 6, 7, 8, 9]4 destination: [9, 8, 7, 6, 5, 4, 3, 2, 1]

 

java編程思想 ListIterator 逆序