迭代器使用异常

Question

您好，即使有可以返回的字符，我的代码也会引发异常。这是我的代码

/** Return true if there is another character for the instance to return. */
    public boolean hasNext() {
        if(cursor<characterSource.length()) {
            return true;
        }
        return false;


    }

    /** Returns the next character in the String. */
    public Character next() throws NoSuchElementException {
        if(hasNext()) {
            int retVal=characterSource.indexOf(cursor);
            return characterSource.charAt(retVal);
        }
        throw new NoSuchElementException();

    }

我在做什么错了？

Answer 1

假设characterSource是String或兼容的东西，我认为您应该删除此行：

int retVal=characterSource.indexOf(cursor);

并调整另一个：

return characterSource.charAt(cursor++);

Answer 2

将您的代码更改为此。

public boolean hasNext() {
    return cursor < characterSource.length();
}

public Character next() throws NoSuchElementException {
    if(hasNext()) {
        return characterSource.charAt(cursor++);
    }
    throw new NoSuchElementException("End of string reached");
}

cursor已经保存了当前字符的索引。没有理由致电characterSource.indexOf(cursor)。