11. public static Iterator reverse(List list) {
12. Collections.reverse(list);
13. return list.iterator();
14. }
15. public static void main(String[] args) {
16. List list = new ArrayList();
17. list.add(” 1”); list.add(”2”); list.add(”3”);
18. for (Object obj: reverse(list))
19. System.out.print(obj + “,”);
20. }
‘What is the result?
A. 3,2, 1,
B. 1, 2, 3,
C. Compilation fails.
D. The code runs with no output.
E. An exception is thrown at runtime.
Answer: C11. public static Collection get() {
12. Collection sorted = new LinkedList();
13. sorted.add(’B”); sorted.add(”C”); sorted.add(”A”);
14. return sorted;
15. }
16. public static void main(String[] args) {
17. for (Object obj: get()) {
18. System.out.print(obj + “, “);
19. }
20. }
What is the result?
A. A, B, C,
B. B, C, A,
C. Compilation fails.
D. The code runs with no output.
E. An exception is thrown at runtime.
Answer: B谁能帮我讲讲这两道题的异同和相关的知识点???
谢谢~~
12. Collections.reverse(list);
13. return list.iterator();
14. }
15. public static void main(String[] args) {
16. List list = new ArrayList();
17. list.add(” 1”); list.add(”2”); list.add(”3”);
18. for (Object obj: reverse(list))
19. System.out.print(obj + “,”);
20. }
‘What is the result?
A. 3,2, 1,
B. 1, 2, 3,
C. Compilation fails.
D. The code runs with no output.
E. An exception is thrown at runtime.
Answer: C11. public static Collection get() {
12. Collection sorted = new LinkedList();
13. sorted.add(’B”); sorted.add(”C”); sorted.add(”A”);
14. return sorted;
15. }
16. public static void main(String[] args) {
17. for (Object obj: get()) {
18. System.out.print(obj + “, “);
19. }
20. }
What is the result?
A. A, B, C,
B. B, C, A,
C. Compilation fails.
D. The code runs with no output.
E. An exception is thrown at runtime.
Answer: B谁能帮我讲讲这两道题的异同和相关的知识点???
谢谢~~
12. Collections.reverse(list);
13. return list.iterator();
14. }
15. public static void main(String[] args) {
16. List list = new ArrayList();
17. list.add(” 1”); list.add(”2”); list.add(”3”);
18. for (Object obj: reverse(list)) //不能遍历一个Iterator
19. System.out.print(obj + “,”);
20. }
‘What is the result?
A. 3,2, 1,
B. 1, 2, 3,
C. Compilation fails.
D. The code runs with no output.
E. An exception is thrown at runtime.
Answer: C11. public static Collection get() {
12. Collection sorted = new LinkedList();
13. sorted.add(’B”); sorted.add(”C”); sorted.add(”A”);
14. return sorted;
15. }
16. public static void main(String[] args) {
17. for (Object obj: get()) { //遍历一个Collection,正确
18. System.out.print(obj + “, “);
19. }
20. }
What is the result?
A. A, B, C,
B. B, C, A,
C. Compilation fails.
D. The code runs with no output.
E. An exception is thrown at runtime.
Answer: B
这种写法,好像只能遍历实现了Iterable的接口
public static void main(String args[]){
ArrayList<Integer> list = new ArrayList<Integer>();
list.add(1);
list.add(2);
Iterator iterator = list.iterator();
for(int i : iterator)
System.out.print(i +" ");
}
}
楼主敲一下这个代码就知道为什么了 是因为Iterator不支持新的for循环的这种写法
至于对的就没什么好说的需要注意的是Collection sorted = new LinkedList();这个你如何加到sorted里去的 就是如何输出的 即FIFO
帮忙讲详细一点Iterator和Collection遍历之间的区别吧,为什么一个可以遍历,另一个不能遍历。
越详细越好~~大侠~~~
原来是不支持的原因。。谢谢~~~FIFO是先进先出的意思吧??谢谢了
LinkedList不支持排序,所以照原样输出~~
你看看Iterator,它名字虽然是Iterator, 但是它不是一个Iterable的。
linkedlist于排序没有关系,它支持类似队列的操作。