Java 中 List 向前和向后遍歷

Java 中 List 向前和向后遍歷

import java.util.*;
public class TestCollectionIterator {
    public static void main(String args[]){
        ArrayList<String> al=new ArrayList<String>();
        al.add("Amit");
        al.add("Vijay");
        al.add("Kumar");
        al.add(1,"Sachin");
        System.out.println("element at 2nd position: "+al.get(2));
        ListIterator<String> itr=al.listIterator();
        System.out.println("traversing elements in forward direction...");
        while(itr.hasNext()){
            System.out.println(itr.next());
        }
        System.out.println("\ntraversing elements in backward direction...");
        while(itr.hasPrevious()){
            System.out.println(itr.previous());
        }
    }
}

參考答案

``` element at 2nd position: Vijay traversing elements in forward direction... Amit Sachin Vijay Kumar

traversing elements in backward direction...
Kumar
Vijay
Sachin
Amit

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