在鋸齒陣列中總結數值

Question

我有一個鋸齒陣列來獲取學生和主題的詳細信息，我使用了2個鋸齒陣列，一個用於學生的詳細信息（名稱和rollno），另一個用於主題的詳細信息（主題和標記），現在我想總結一下特定學生的所有標記，誰能告訴我怎麼去解決這個問題，下面是我的整個代碼。

public void GetStudentDetails() 
     { 

      Console.WriteLine("Please enter number of Students"); 
      int STUDENTS = Convert.ToInt32(Console.ReadLine()); 
      Console.WriteLine("Please enter number of Subjects"); 
      int SUBJECTS = Convert.ToInt32(Console.ReadLine()); //0 is reserved for the student name, so the marks starts from the index 1, hence if you set the marks for 3, it will ask for 2 marks 


      string[][] student_details = new string[STUDENTS][]; 
      string[][] subject_details = new string[SUBJECTS][]; 
      string[][] result_details = new string[STUDENTS][]; 

      StringBuilder stud_sub_info = new StringBuilder(); 
      stud_sub_info.Append("Name\tRoll-No\t"); 
      for (int a = 0; a < STUDENTS; a++) 
      { 
       student_details[a] = new string[STUDENTS * 2]; 
       for (int b = 0; b < 2; b++) 
       { 
        Console.WriteLine("Enter Student {0} {1}:", a + 1, (b == 0) ? "Name" : "Roll-No"); 
        student_details[a][b] = Console.ReadLine(); 
       } 
       for (int c = 0; c < SUBJECTS; c++) 
       { 
        subject_details[c] = new string[SUBJECTS * 2]; 
        for (int d = 0; d < 2; d++) 
        { 
         if (d == 0) 
         { 
          Console.WriteLine("Enter Name for Subject {0}", c + 1); 
          subject_details[c][d] = Console.ReadLine(); 
          stud_sub_info.Append(subject_details[c][d] + "\t"); 
         } 
         else 
         { 
          Console.WriteLine("Enter Marks for {0}", subject_details[c][d - 1]); 
          subject_details[c][d] = Console.ReadLine(); 
         } 
        } 
       } 
      } 
      Console.WriteLine(stud_sub_info.ToString()); 
      for (int a = 0; a < STUDENTS; a++) 
      { 
       for (int b = 0; b < 2; b++) 
       { 
        Console.Write(student_details[a][b] + "\t"); 
       } 
       for (int c = 0; c < SUBJECTS; c++) 
       { 
        for (int d = 0; d < 2; d++) 
        { 
         Console.Write(subject_details[c][d] + "\t"); 
        } 
       } 
      } 
     } 

Answer 1

我當然不會使用這樣的鋸齒狀數組。它使編碼困難。

例如，在您的代碼中，您正在爲每個學生捕獲主題標記，但是當您清除之前學生的數據時。 subject_details交錯排列的數組沒有學生的索引。隨時隨地覆蓋數據。您需要將該陣列聲明爲string[][][]。

這裏是你的代碼，更簡單，將工作：

string[][] student_details = new string[STUDENTS][]; 
string[][][] subject_details = new string[STUDENTS][][]; 
string[][] result_details = new string[STUDENTS][]; 

for (int a = 0; a < STUDENTS; a++) 
{ 
    student_details[a] = new string[STUDENTS * 2]; 
    subject_details[a] = new string[SUBJECTS][]; 
    Console.WriteLine("Enter Student {0} {1}:", a + 1, "Name"); 
    student_details[a][0] = Console.ReadLine(); 
    Console.WriteLine("Enter Student {0} {1}:", a + 1, "Roll-No"); 
    student_details[a][1] = Console.ReadLine(); 
    for (int c = 0; c < SUBJECTS; c++) 
    { 
     subject_details[a][c] = new string[SUBJECTS * 2]; 
     Console.WriteLine("Enter Name for Subject {0}", c + 1); 
     subject_details[a][c][0] = Console.ReadLine(); 
     Console.WriteLine("Enter Marks for {0}", subject_details[a][c][0]); 
     subject_details[a][c][1] = Console.ReadLine(); 
    } 
} 
for (int a = 0; a < STUDENTS; a++) 
{ 
    Console.Write(student_details[a][0] + "\t"); 
    Console.Write(student_details[a][1] + "\t"); 
    for (int c = 0; c < SUBJECTS; c++) 
    { 
     Console.Write(subject_details[a][c][0] + "\t"); 
     Console.Write(subject_details[a][c][1] + "\t"); 
    } 
} 

現在因爲我們忽略了這一事實，每一個學生都必須有相同數量的科目和您允許的非數字進入主題分數，你可以使用下面的LINQ查詢將鋸齒狀的數組變成可行的。

var query = 
    from i in Enumerable.Range(0, STUDENTS) 
    let Name = student_details[i][0] 
    let RollNo = student_details[i][1] 
    let Subjects = (
     from j in Enumerable.Range(0, SUBJECTS) 
     let Subject = subject_details[i][j][0] 
     let Marks = int.Parse(subject_details[i][j][1]) 
     select new { Subject, Marks } 
    ) 
    select new { Name, RollNo, Subjects }; 

這讓我看起來像這樣的結構：

現在你可以使用這個查詢來獲取佔總分：

var results = 
    query 
     .Select(x => new 
     { 
      x.Name, 
      TotalMarks = x.Subjects.Sum(y => y.Marks) 
     }); 

現在這個樣子：

Answer 2

使用Linq，Collections和創建類而不是參差不齊的數組會更容易。這將允許你將1個學生連接到許多課程，並且在每門課程中都有許多作業。然後LINQ的語句如：

Sum(x => x.StudentGrade) 

下面是什麼，我會在開始時只是爲了得到什麼，我可以用資金做一個想法存根複印件，以及其他信息：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Threading.Tasks; 

namespace StudentManagement { 
    public class Student { 

    public static void Main(string[] args) { 
     List<Student> students = new List<Student>(); 

     Console.Write("Enter number of students: "); 
     int numStudents = int.Parse(Console.ReadLine()); 

     for (int i = 0; i < numStudents; i++) { 
     Student s = new Student(); 
     students.Add(s); 
     } 

     Console.Write("Press any key to continue..."); 
     Console.ReadKey(true); 
    } 

    public string FirstName { get; set; } 
    public List<Course> Courses { get; set; } 

    public Student() { 
     this.Courses = new List<Course>(); 

     Console.Write("Enter First Name: "); 
     this.FirstName = Console.ReadLine(); 

     Console.Write("Enter in number of courses: "); 
     int numCourses = int.Parse(Console.ReadLine()); 

     for (int i = 0; i < numCourses; i++) { 
     Course course = new Course(); 
     this.Courses.Add(course); 
     } 

    } 
    } 

    public class Course { 
    public string Title { get; set; } 
    public string Code { get; set; } 
    public string Section { get; set; } 
    public List<Assignment> Assignments { get; set; } 

    public Course() { 
     this.Assignments = new List<Assignment>(); 

     // Set Title, Code, Section 
     Console.Write("Enter nuber of assignments: "); 
     int numAssignments = int.Parse(Console.ReadLine()); 

     for (int i = 0; i < numAssignments; i++) { 
     Assignment assignment = new Assignment(); 
     this.Assignments.Add(assignment); 
     } 

    } 
    } 

    public class Assignment { 
    public string Name { get; set; } 
    public double MaxGrade { get; set; } 
    public double StudentGrade { get; set; } 

    public Assignment() { 
     // Prompt for Name, MaxGrade, StudentGrade 
    } 
    } 
}