程序代码：

    public String[] finddate(String in) {
        datenode position = head;
        int count = 0;
        String[] result = new String[this.countdate()];
        int n = 1;
        do {

            if (position != null) {
                while (position.date!=in) {
                    
                    position = position.next;
                }
                if (position.date==in)
                    result[count] = "the location is " + (count+1);

            } else
                System.out.println("no date at all");
            n++;
            count++;
            position = position.next;
        } while (n >= this.countdate());
        return result;
    }