Question

Java问题 iterator

public int sumArrayRecursive(int[] numbers)
{
int sum = 0;
for(int i = 0; i < numbers.length; i++)
{
sum = sum + numbers[i];
}
return sum;
}

public int sumArrayRecursive(List<Integer> numbers)
{
int sum = 0;
for(int i : numbers)
{
sum = sum + i;
}
return sum;

}

需要改写成使用iterator的方法

Answer 1

	public int sumArrayRecursive(List<Integer> numbers) {

		int sum = 0;
		Iterator<Integer> it = numbers.iterator();
		while (it.hasNext()) {
			sum = sum + it.next();
		}
		return sum;

	}

追问

上面一个怎么做呢。

追答

public int sumArrayRecursive(int[] numbers) {
int sum = 0;
List list = Arrays.asList(numbers);
Iterator<Integer> it = list.iterator();
while (it.hasNext()) {
sum = sum + it.next();
}
return sum;
}

追问

java.lang.ClassCastException: [I cannot be cast to java.lang.Integer
at ListProcessor.sumArrayIterative(ListProcessor.java:114)

有个Error，说最后一句有问题

追答

public  int sumArrayRecursive(int[] numbers) {
    int sum = 0;
    List list = Arrays.asList(ArrayUtils.toObject(numbers));
    Iterator<Integer> it = list.iterator();
    while (it.hasNext()) {
        sum = sum + it.next();
    }
    return sum;
}

改成以上代码