Алексей's questions

给出了需要分析和通过的单元测试。

[TestCase("07K4M1DZ-BZ", '7', '4', 'Z')]
[TestCase("19K06M1DI-AZ", '9', '6', 'I')]
[TestCase("31K008M1DJ-KZ", '1', '8', 'J')]
public void GetSpecialCodes(string serialNumber, char expectedCode1, char expectedCode2, char expectedCode3)
{
    // Act
    UsingIndexer.GetSpecialCodes(serialNumber, out char code1, out char code2, out char code3);
 
    // Assert
    Assert.That(expectedCode1, Is.EqualTo(code1));
    Assert.That(expectedCode2, Is.EqualTo(code2));
    Assert.That(expectedCode3, Is.EqualTo(code3));
}

一切看起来都很简单：第一个应该返回 7（第二个元素），第二个应该返回 6（第五个元素），第三个应该返回 J（第十个元素）让我们尝试实现这个方法

public static void GetSpecialCodes(string serialNumber, out char expectedCode1, out char expectedCode2, out char expectedCode3)
{
    ArgumentNullException.ThrowIfNull(serialNumber);
 
    expectedCode1 = serialNumber[1];  // Второй символ
    expectedCode2 = serialNumber[5];  // Шестой символ
    expectedCode3 = serialNumber[9];  // Десятый символ
}

测试的结果只有第三次测试通过，测试结果很奇怪（我附上截图） 第一次测试：

[TestCase("07K4M1DZ-BZ", '7', '4', 'Z')]
Assert.That(expectedCode2, Is.EqualTo(code2))
Expected: '1'
But was: '4'
Второй тест: [TestCase("19K06M1DI-AZ", '9', '6', 'I')]
Assert.That(expectedCode2, Is.EqualTo(code2))
Expected: 'M'
But was: '6'

难以理解的期望值为什么都是code2而不是1？？？

如果更改方法中的任何一行，所有测试都将不正确，并且预期值将变得不同。这个测试有什么问题，或者我只是在某个地方犯了语法错误？

学习php。这是数据库的输出代码。第一行有语法错误。我不知道是什么问题。变量名没有错误

<?php $kommen = mysqli_query($con, "SELECT * FROM 'comments' ORDER BY 'id'") ?>
<?php while($kom = mysqli_fetch_assoc($kommen)) { ?>

        <div class="komment">
          <img src="123.png">
          <div class="name"><?php echo $kom['name'] ?></div>
          <hr>
          <div class="message"><?php echo $kom['message'] ?></div>
        </div>
<?php } ?>

C# 中来自 Project Euler 的问题 8

73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450

找出给定数字中连续十三位数字的最大乘积。

这是我写的代码

DateTime startTime = DateTime.Now;
            const String p = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";


            int largest = 0;
            int numm = 0;

            for (int i = 0; i < p.Length - 12; i++) {
                numm = int.Parse(p.Substring(i, 1)) *
                           int.Parse(p.Substring(i + 1, 1)) *
                           int.Parse(p.Substring(i + 2, 1)) *
                           int.Parse(p.Substring(i + 3, 1)) *
                           int.Parse(p.Substring(i + 4, 1)) *
                           int.Parse(p.Substring(i + 5, 1)) *
                           int.Parse(p.Substring(i + 6, 1)) *
                           int.Parse(p.Substring(i + 7, 1)) *
                           int.Parse(p.Substring(i + 8, 1)) *
                           int.Parse(p.Substring(i + 9, 1)) *
                           int.Parse(p.Substring(i + 10, 1)) *
                           int.Parse(p.Substring(i + 11, 1)) *
                           int.Parse(p.Substring(i + 12, 1));
                if (numm > largest) {
                    largest = numm;
                }
            }
            
            Console.WriteLine(largest);
            DateTime stopTime = DateTime.Now;
            TimeSpan duration = stopTime - startTime;
            Console.WriteLine("Solution took {0} ms", duration.TotalMilliseconds);
            Console.ReadLine();

答案是 2091059712，但它是错误的。告诉我我做错了什么。

有一个表单加载

private void Form1_Load(object sender, EventArgs e)
        {
            Teams team1 = new Teams("Teamname", "TrainerName", "Country");
            team1.DisplayInfo();
        }

Teams 类文件有一个 DisplayInfo 方法

public void DisplayInfo()
        {
            DataTable table = new DataTable();
            table.Columns.Add("Team Name", typeof(string));
            table.Columns.Add("Trainer", typeof(string));
            table.Columns.Add("Country", typeof(string));
            table.Rows.Add(TeamName, TeamTrainer, TeamCountry);
            dataGridView1.DataSource = table;
        }

引发错误 datagridview1 在当前上下文中不存在。是否有可能以某种方式将 datagridview 的使用添加到 Form.cs 之外的其他文件中，如果可以，如何？没有找到太多答案。还是我需要以不同的方式描述 DisplayInfo() 方法？告诉我怎么做。

给定一个数组。比较数组的第一个和第二个元素。如果第二个元素小于第一个元素，则交换它们。然后对第二个和第三个，...，倒数第二个和最后一个元素执行相同的操作。数组最后一个元素的结果是多少？

 public static void swap(int a, int b)
        {
            int tmp;
            tmp = a;
            a = b;
            b = tmp;
        }
        static void Main(string[] args)
        {
            int[] array = new int[10];
            Random rand = new Random();
            for(int i=0; i<array.Length; i++)
            {
                array[i] = rand.Next(20);
                Console.Write(array[i] + " ");
            }
            for(int i=0; i<array.Length; i++)
            {
                if(array[i] > array[i + 1])
                {
                        swap(array[i], array[i + 1]); 
                }   
            }
            Console.WriteLine();
            for (int i = 0; i < array.Length; i++)
            {
                
                Console.Write(array[i] + " ");
            }
        }

目前 if(array[i] > array[i + 1]) 我得到一个错误。并且索引超出了数组的范围。告诉我如何解决这个问题？

这是一个由人名和年龄组成的结构。如何从中删除第 n 个元素并显示没有它的结构？或者是否可以创建一个新结构并将除 n 元素之外的所有内容复制到其中？

public struct mans
        {
            public string name;
            public int age;

            public mans(string _name, int _age) : this()
            {
                this.name = _name;
                this.age = _age;
            }

        }
 static void Main(string[] args)
    {
         
            List<mans> man = new List<mans>();
            int m = 4;
            
            for(int i=0; i<m; i++)
            {
                string oneMan = Convert.ToString(Console.ReadLine());
                string[] wrMan = oneMan.Split(new char[] { ' ' });
                man.Add(new mans(wrMan[0], Convert.ToInt32(wrMan[1])));
            }
            for(int i=0; i<m; i++)
            {
                WriteLine(man[i].name + " " + man[i].age);
            }
        int n=Convert.ToInt32(Console.ReadLine());
    }

请帮忙。您需要创建一棵二叉树并输出这棵树的最长路径。我确实向树中添加了元素并在屏幕上显示树，但我不知道如何继续。

#define _CRT_SECURE_NO_WARNINGS
#include <stdlib.h>
#include <stdio.h>
struct TNode
{
    int info; 
    struct TNode* left, * right;
};
typedef struct TNode Node;
void push(Node** t, int a)
{
    if (*t == NULL) 
    {
        *t = (Node*)malloc(sizeof(Node)); 
        (*t)->info = a;
        (*t)->left = (*t)->right = NULL; 
            return;
    }
    
    if (a > (*t)->info) push(&((*t)->right), a); 
    else push(&((*t)->left), a); 
}
 
void showTree(Node* t)
{
    if (t == NULL) return;
    showTree(t->left); 
    printf("%i ", t->info); 
    showTree(t->right); 
}
int main()
{
    Node* tree = NULL;
    int n; 
    int s; 
    printf("Enter number of items ");
    scanf("%i", &n);
    for (int i = 0; i < n; ++i)
    {
        printf("Enter information ");
        scanf("%i", &s); 
        push(&tree, s); 
    }
    printf("Tree\n");
    showTree(tree);
    return 0;
}