循环的两种方式和迭代

package com.zljy;import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import java.util.Set;public class test {public static void main(String args[]){int[] arr = {1,2,3,4};//for(int i=0;i<arr.length;i++){//System.out.print(arr[i]);//}//for(int l : arr){//System.out.print(l);//}List<String> list = new ArrayList<String>();list.add("a");list.add("b");list.add("c");for(int i =0;i<list.size();i++){System.out.println(list.get(i));}for(String l : list){System.out.println(l);}for(Iterator it = list.iterator();it.hasNext();){System.out.println(it.next());}//Map map = new HashMap();//map.put("a", 1);//map.put("b", 2);//map.put("c", 3);//Set set = map.entrySet();//Iterator it = set.iterator();//while(it.hasNext()){//System.out.println(it.next());//}}}