c#链表，返回多个条目

Question

我正在尝试创建一个链接列表，类似于鸟类调查类型的东西，并且我试图有一个最终输出，它返回我输入的所有物种以及我输入每个物种的次数。现在输出计算了我输入的每只不同的鸟，但它没有在报告的末尾为我输入的每只鸟单独计数，我不知道该怎么做。我已经为此烦恼了好几个小时了，我觉得我已经很接近了，如果可以请帮助

class Program
{
    public class Node
    {

        /* You add the type of bird and a count of 
         * how many times that bird is said. 
         * Then you use a method to print out 
         * the types of birds and how many times each bird was said*/
        public string bird;
        public Node next;
        public Node(string i)
        {
            bird = i;
            next = null;
        }
        public void getReport()
        {
            Console.Write("|" + bird + "|->");
            if (next != null)
            {
                next.getReport();
            }
        }
        public void AddToEnd(string bird)
        {
            if (next == null)
            {
                next = new Node(bird);
            }
            else
            {
                next.AddToEnd(bird);
            }
        }

        public class BirdList
        {
            public Node headNode;

            public BirdList()
            {
                headNode = null;
            }
            public void AddToEnd(string bird) //method to add to the end of a list 
            {
                if (headNode == null)
                {
                    headNode = new Node(bird);
                }
                else
                {
                    headNode.AddToEnd(bird);
                }
            }
            public void AddToBeginning(string bird) //add to the beginning of a list
            {
                if (headNode == null)
                {
                    headNode = new Node(bird);                      
                }
                else
                {
                    Node temp = new Node(bird);
                    temp.next = headNode;
                    headNode = temp;
                }
            }
            public void getReport()
            {
                if (headNode != null)
                {
                    headNode.getReport();
                }
            }
            public int getCount(string bird)
            {                 
                Node current = headNode;
                int count = 0;
                while (current!= null)
                {
                    if (current.bird == bird)
                    {
                        count++;
                    }
                    current = current.next; 
                }
                return count;
            }

        }
        static void Main(string[] args)
        {
            BirdList birdList = new BirdList();

            string userInput = "";
            while (userInput != "done")
            {
                Console.WriteLine("Please enter a bird:");
                userInput = Console.ReadLine();
                if (userInput == "done")
                {
                    break;
                }
                birdList.AddToEnd(userInput);
                Console.WriteLine(birdList.getCount(userInput));
            }

            birdList.getReport();
            Console.ReadLine();

输出看起来像这样：

Answer 1

当您运行报告功能时，它似乎没有被指示实际计算它遇到的每个单独项目的数量。

解决这个问题的直接方法是遍历列表并将遇到的每个单独的字符串保存到字典中，然后在发现字典已经包含重复项时增加值。

Node n = birdList.headNode;
Dictionary<string,int> dict = new Dictionary<string,int>();
while(n!=null){
    if(dict.ContainsKey(n.bird))
    {
        dict[n.bird]++;
    }else{
        dict.Add(n.bird,1);
    }
    n=n.next;
}

字典应该包含所有的鸟作为键，它们的数量作为值。

Answer 2

您的代码很好，只是缺少一些东西。一方面，每只鸟都需要一个柜台。一旦它在列表中，也不需要再次添加鸟。我稍微重写了您的代码，并将 cmets 放入您查看。给你：

class Program
    {
        public class Node
        {

            /* You add the type of bird and a count of 
             * how many times that bird is said. 
             * Then you use a method to print out 
             * the types of birds and how many times each bird was said*/
            public string bird;
            public Node next;
            public int count; // each bird needs a counter
            public Node(string i)
            {
                bird = i;
                next = null;
                count = 0;
            }
            public void getReport()
            {
                Console.Write("|" + bird + "|->" +  count );
                if (next != null)
                {
                    next.getReport();
                }
            }
            public void AddToEnd(string bird)
            {
                if (this.bird != bird) // if the bird is already in the list, it wont add it in again.
                {
                    if (next == null)
                    {
                        next = new Node(bird);
                    }
                    else
                    {
                        next.AddToEnd(bird);
                    }
                }
            }

            public class BirdList
            {
                public Node headNode;

                public BirdList()
                {
                    headNode = null;
                }
                public void AddToEnd(string bird) //method to add to the end of a list if bird is not already in the list. 
                {
                    if (headNode == null)
                    {
                        headNode = new Node(bird);
                    }
                    else
                    {
                        headNode.AddToEnd(bird);
                    }
                }
                public void AddToBeginning(string bird) //add to the beginning of a list
                {
                    if (headNode == null)
                    {
                        headNode = new Node(bird);
                    }
                    else
                    {
                        Node temp = new Node(bird);
                        temp.next = headNode;
                        headNode = temp;
                    }
                }
                public void getReport()
                {
                    if (headNode != null)
                    {
                        headNode.getReport();
                    }
                }
                public int getCount(string bird)
                {
                    Node current = headNode;
                    int count = 0;
                    while (current != null)
                    {
                        if (current.bird == bird)
                        {
                            current.count++; // once the bird is found, increment the counter.
                            count = current.count; // set the birds counter to the count.
                        }
                        current = current.next;
                    }

                    return count;
                }

            }
            static void Main(string[] args)
            {
                BirdList birdList = new BirdList();

                string userInput = "";
                while (userInput != "done")
                {
                    Console.WriteLine("Please enter a bird:");
                    userInput = Console.ReadLine();
                    if (userInput == "done")
                    {
                        break;
                    }
                    birdList.AddToEnd(userInput);
                    Console.WriteLine(birdList.getCount(userInput));
                }

                birdList.getReport();
                Console.ReadLine();
            }
        }
    }