【Java学习笔记】循环操作

import java.util.ArrayList;
import java.util.Iterator;


public class Practice {

    public static void main(String[] args) {
        int[] ary=new int [6];
        ary[0] = 3;
        ary[1] = 4;
        ary[2] = 5;
        ary[3] = 6;
        ary[4] = 7;
        ary[5] = 8;
        
        int i=0;
        while (i<ary.length) {
            System.out.print(ary[i]);
            i++;
        }
        
        System.out.println();
        
        i=0;
        do {
            System.out.print(ary[i]);
            i++;
        } while (i<ary.length);
        
        System.out.println();
        
        for (i = 0; i < ary.length; i++) {
            System.out.print(ary[i]);
        }
        System.out.println();
        
        for (int j : ary) {
            System.out.print(j);
        }
        System.out.println();
        
        ArrayList<Integer> arr = new ArrayList<Integer>();
        arr.add(new Integer(1));
        arr.add(new Integer(2));
        arr.add(new Integer(3));
        arr.add(new Integer(4));
        
        for (int k = 0; k < arr.size(); k++) {
            System.out.print(arr.get(k)+" ");
        }
        System.out.println();
        
        Iterator<Integer> iter= arr.iterator();//使用迭代器
        while (iter.hasNext()) {
            System.out.print(iter.next()+" ");
        }

        System.out.println();
        
        for (Integer in : arr) {//使用增强的for循环--foreach，完全的迭代最简单
                                     //arr集合变量可以是数组或者实现了Iterator接口的集合类。
            System.out.print(in + " ");
        }
    }
}