用于练习的自定义链表 c# - 不确定为什么我的插入不起作用


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
    class Program
    {
        class node
        {
            public int data;
            public node next;
            public node(int value)
            {
                next = null;
                data = value;
            }
            public void addFront(node head, int value)
            {
                var tempNode = new node(value);
                tempNode.next = head;
                head = tempNode;
            }
            public void addBack(node head, int value)
            {
                var insertNode = new node(value);
                var traverseNode = head;
                while (traverseNode != null)
                {
                    if (traverseNode.next == null)
                    {
                        traverseNode.next = insertNode;
                        insertNode.data = value;
                    }
                    traverseNode = traverseNode.next;
                }
            }
            public void printList(node head)
            {
                var counter = 0;
                var traverseNode = head;
                while (traverseNode != null)
                {
                    Console.WriteLine("LL item {0}: {1}", counter, traverseNode.data);
                    traverseNode = traverseNode.next;
                    counter++;
                }
            }
            public int deleteFront(node head)
            {
                //Don't need to delete the memory because the garbage collector handles that in c# (at least by my understanding). If this were C, I'd have to use free, and in C++ I'd use keyword Delete
                var returnValue = head.data;
                head = head.next;
                return returnValue;
            }
            public int deleteBack(node head)
            {
                node traverseNode = head;
                node traverseNodeTrailer = head;
                if (traverseNode == null)
                {
                    return 0;
                }
                while (traverseNode != null)
                {
                    if (traverseNode.next == null)
                    {
                        traverseNodeTrailer.next = null;
                        break;
                    }
                    traverseNodeTrailer = traverseNode;
                    traverseNode = traverseNode.next;
                }
                return traverseNode.data;
            }
            public void deleteMiddle(node middleNode)
            {
                var traverseNode = middleNode;
                while (traverseNode != null)
                {
                    if (traverseNode.next.next == null)
                    {
                        traverseNode.data = traverseNode.next.data;
                        traverseNode.next = null;
                        break;
                    }
                    traverseNode.data = traverseNode.next.data;
                    traverseNode = traverseNode.next;
                }
            }
            public node search(node head, int value)
            {
                var traverseNode = head;
                while (traverseNode != null)
                {
                    if (traverseNode.data == value)
                        return traverseNode;
                    traverseNode = traverseNode.next;
                }
                return null;//failed to find the value in the linked list
            }
        }
        static void Main(string[] args)
        {
            Int32 userMenuInput = 0;
            var running = true;
            int userNodeInput = 0;
            node head = null;
            while (running)
            {
                Console.WriteLine("Enter a number depending on the operation you would like to perform.");
                Console.WriteLine("1 - Insert node of specified value; 2 - Delete a node and return the value; 3 - Search for a node with a specified value; 4 - Print the list values. *All other values exit");
                userMenuInput = Convert.ToInt32(Console.ReadLine());//get user input for what they want to do
                switch (userMenuInput)
                {
                    case 1:
                        Console.WriteLine("Enter a number you'd like to insert into the linked list.");
                        userNodeInput = Convert.ToInt32(Console.ReadLine());//get user input for value to insert
                        if (head == null)
                        {
                            head = new node(userNodeInput);
                            break;
                        }
                        head.addFront(head, userNodeInput);
                        break;
                    case 2:
                        if (head == null)
                        {
                            Console.WriteLine("The list is empty - cannot delete.");
                            break;
                        }
                        userNodeInput = head.deleteFront(head);
                        Console.WriteLine("{0} is the value that was deleted from the front of the list.", userNodeInput);
                        break;
                    case 3:
                        Console.WriteLine("What is the value you'd like to search for in the list?");
                        userNodeInput = Convert.ToInt32(Console.ReadLine());
                        if (head == null)
                        {
                            //do nothing
                        }
                        else if (head.search(head, userNodeInput) != null)
                        {
                            Console.WriteLine("That value was found");
                            break;
                        }
                        Console.WriteLine("That value was not found.");
                        break;
                    case 4:
                        if (head == null)
                        {
                            Console.WriteLine("The list has nothing to print.");
                            break;
                        }
                        head.printList(head);
                        break;
                    default:
                        running = false;
                        break;
                }
            }
        }
    }
}

免责声明:我对c#非常陌生-只是在过去的一周左右使用它。我将感谢您提供的任何优化提示,但现在,我只是想让它运行起来。

所以,这是正确插入1个元素,但仅此而已。如果元素在第一个链接中,则查找该元素。删除似乎根本不起作用。它不会抛出任何错误,但也不会删除第一个链接。注意:到目前为止,我的一些函数还没有使用过,所以不用担心提到这一点——我知道。

谢谢大家!

如果你想修改传递给addFront方法的参数,可以使用ref:

public void addFront(ref node head, int value)
        {
            var tempNode = new node(value);
            tempNode.next = head;
            head = tempNode;
        }

.

head.addFront(ref head, userNodeInput);

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