CSharp_孙艺菡_笃实45

Homework/Program.cs

@@ -1,51 +1,69 @@
 // See https://aka.ms/new-console-template for more information
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.IO;
+using System.Xml.Linq;
 
 namespace StudentManagementSystem
 {
     // 成绩等级枚举
     public enum Grade
     {
         // TODO: 定义成绩等级 F(0), D(60), C(70), B(80), A(90)
-
+        F = 0,
+        D = 60,
+        C = 70,
+        B = 80,
+        A = 90
     }
 
     // 泛型仓储接口
     public interface IRepository<T>
     {
         // TODO: 定义接口方法
-        // Add(T item)
-        // Remove(T item) 返回bool
-        // GetAll() 返回List<T>
-        // Find(Func<T, bool> predicate) 返回List<T>
+        void Add(T item);
+        bool Remove(T item);
+        List<T> GetAll();
+        List<T> Find(Func<T, bool> predicate);
 
     }
 
     // 学生类
     public class Student : IComparable<Student>
     {
         // TODO: 定义字段 StudentId, Name, Age
-
-
+        public readonly string StudentId;
+        public readonly string Name;
+        public readonly int Age;
+
         public Student(string studentId, string name, int age)
         {
             // TODO: 实现构造方法，包含参数验证（空值检查）
-
+            if (string.IsNullOrEmpty(studentId)) 
+                throw new ArgumentNullException("学号不能为空");
+            if (string.IsNullOrWhiteSpace(name))
+                throw new ArgumentException("姓名不能为空");
+            if (age <= 0)
+                throw new ArgumentException("年龄不能为空");
+
+            StudentId = studentId;
+            Name = name;
+            Age = age;
         }
 
         public override string ToString()
         {
             // TODO: 返回格式化的学生信息字符串
-
+            return $"学号: {StudentId}, 姓名: {Name}, 年龄: {Age}";
         }
 
         // TODO: 实现IComparable接口，按学号排序
         // 提示：使用string.Compare方法
         public int CompareTo(Student? other)
         {
-
+            if (other == null) return 1;
+            return string.Compare(StudentId, other.StudentId, StringComparison.Ordinal);
         }
 
         public override bool Equals(object? obj)
@@ -63,18 +81,27 @@ public override int GetHashCode()
     public class Score
     {
         // TODO: 定义字段 Subject, Points
-
-
+        public readonly string Subject;
+        public readonly double Points;
+
+
         public Score(string subject, double points)
         {
             // TODO: 实现构造方法，包含参数验证
-
+            Subject = subject;
+            Points = points;
+
+            if (string.IsNullOrWhiteSpace(subject))
+                throw new ArgumentException("科目不能为空");
+            if (points < 0 || points > 100)
+                throw new ArgumentOutOfRangeException("分数必须在0-100之间");
+
         }
 
         public override string ToString()
         {
             // TODO: 返回格式化的成绩信息
-
+            return $"科目: {Subject}, 分数: {Points:F1}";
         }
     }
 
@@ -83,39 +110,63 @@ public class StudentManager : IRepository<Student>
     {
         // TODO: 定义私有字段存储学生列表
         // 提示：使用List<Student>存储
-
+        private List<Student> students = new List<Student>();
+
 
         public void Add(Student item)
         {
             // TODO: 实现添加学生的逻辑
             // 1. 参数验证
             // 2. 添加到列表
-
+            if (item == null)
+                throw new ArgumentNullException(nameof(item), "学生对象不能为空");
+            if (students.Contains(item))
+                throw new InvalidOperationException($"学号为{item.StudentId}的学生已存在");
+
+            students.Add(item);
+
         }
 
         public bool Remove(Student item)
         {
             // TODO: 实现Remove方法
-
+            return students.Remove(item);
         }
 
         public List<Student> GetAll()
         {
             // TODO: 返回学生列表的副本
-
+            return new List<Student>(students);
         }
 
         public List<Student> Find(Func<Student, bool> predicate)
         {
             // TODO: 使用foreach循环查找符合条件的学生
+            List<Student> result = new List<Student>();
+            foreach (var student in students)
+            {
+                if (predicate(student))
+                {
+                    result.Add(student);
+                }
+            }
+            return result;
 
         }
 
         // 查找年龄在指定范围内的学生
         public List<Student> GetStudentsByAge(int minAge, int maxAge)
         {
             // TODO: 使用foreach循环和if判断实现年龄范围查询
-
+            List<Student> result = new List<Student>();
+            foreach (var student in students)
+            {
+                if (student.Age >= minAge && student.Age <= maxAge)
+                {
+                    result.Add(student);
+                }
+            }
+            return result;
         }
     }
 
@@ -124,41 +175,87 @@ public class ScoreManager
     {
         // TODO: 定义私有字段存储成绩字典
         // 提示：使用Dictionary<string, List<Score>>存储
-
+        private Dictionary<string, List<Score>> scores = new Dictionary<string, List<Score>>();
+
 
         public void AddScore(string studentId, Score score)
         {
             // TODO: 实现添加成绩的逻辑
             // 1. 参数验证
             // 2. 初始化学生成绩列表（如不存在）
             // 3. 添加成绩
-
+            if (string.IsNullOrWhiteSpace(studentId))
+                throw new ArgumentException("学号不能为空");
+            if (score == null)
+                throw new ArgumentNullException(nameof(score));
+
+            if (!scores.ContainsKey(studentId))
+            {
+                scores[studentId] = new List<Score>();
+            }
+            scores[studentId].Add(score);
+
         }
 
         public List<Score> GetStudentScores(string studentId)
         {
             // TODO: 获取指定学生的所有成绩
-
+            return new List<Score>(scores[studentId]);
         }
 
         public double CalculateAverage(string studentId)
         {
             // TODO: 计算指定学生的平均分
             // 提示：使用foreach循环计算总分，然后除以科目数
-
+            var studentScores = GetStudentScores(studentId);
+            if (studentScores.Count == 0)
+                return 0;
+
+            double total = 0;
+            foreach (var score in studentScores)
+            {
+                total += score.Points;
+            }
+            return total / studentScores.Count;
+
         }
 
         // TODO: 使用模式匹配实现成绩等级转换
         public Grade GetGrade(double score)
         {
-
+            if (score >= 90)
+                return Grade.A;
+            else if (score >= 80)
+                return Grade.B;
+            else if (score >= 70)
+                return Grade.C;
+            else if (score >= 60)
+                return Grade.D;
+            else
+                return Grade.F;
+
         }
 
         public List<(string StudentId, double Average)> GetTopStudents(int count)
         {
             // TODO: 使用简单循环获取平均分最高的学生
             // 提示：可以先计算所有学生的平均分，然后排序取前count个
-
+            var studentAverages = new List<(string StudentId, double Average)>();
+            foreach (var studentId in scores.Keys)
+            {
+                studentAverages.Add((studentId, CalculateAverage(studentId)));
+            }
+
+            var sortedStudentAverages = studentAverages.OrderByDescending(s => s.Average).ToList();
+
+            // 取前count名
+            var result = new List<(string, double)>();
+            for (int i = 0; i < Math.Min(count, studentAverages.Count); i++)
+            {
+                result.Add(studentAverages[i]);
+            }
+            return result;
+
         }
 
         public Dictionary<string, List<Score>> GetAllScores()
@@ -177,7 +274,16 @@ public void SaveStudentsToFile(List<Student> students, string filePath)
             try
             {
                 // 在这里实现文件写入逻辑
-
+                using (StreamWriter writer = new StreamWriter(filePath))
+                {
+                    writer.WriteLine("StudentId,Name,Age");
+                    foreach (var student in students)
+                    {
+                        writer.WriteLine($"{student.StudentId},{student.Name},{student.Age}");
+                    }
+                }
+                Console.WriteLine($"学生数据已成功保存到 {filePath}");
+
             }
             catch (Exception ex)
             {
@@ -194,7 +300,18 @@ public List<Student> LoadStudentsFromFile(string filePath)
             try
             {
                 // 在这里实现文件读取逻辑
-
+                using (StreamReader reader = new StreamReader(filePath))
+                {
+                    string? header = reader.ReadLine();
+                    string? line;
+
+                    while ((line = reader.ReadLine()) != null)
+                    {
+                        string[] parts = line.Split(',');
+                    }
+                }
+                Console.WriteLine($"从 {filePath} 成功读取学生数据");
+
             }
             catch (Exception ex)
             {
@@ -241,22 +358,49 @@ static void Main(string[] args)
                 // 3. 测试年龄范围查询
                 Console.WriteLine("\n3. 查找年龄在19-20岁的学生:");
                 // TODO: 调用GetStudentsByAge方法并显示结果
-
+                var ageRangeStudents = studentManager.GetStudentsByAge(19, 20);
+                foreach (var student in ageRangeStudents)
+                {
+                    Console.WriteLine(student);
+                }
 
                 // 4. 显示学生成绩统计
                 Console.WriteLine("\n4. 学生成绩统计:");
                 // TODO: 遍历所有学生，显示其成绩、平均分和等级
-
+                foreach (var student in studentManager.GetAll())
+                {
+                    Console.WriteLine($"{student.Name} 的成绩 :");
+                    var scores = scoreManager.GetStudentScores(student.StudentId);
+                    foreach (var score in scores)
+                    {
+                        Console.WriteLine(score);
+                    }
+                    double avg = scoreManager.CalculateAverage(student.StudentId);
+                    Grade grade = scoreManager.GetGrade(avg);
+                    Console.WriteLine($"平均分: {avg}, 等级: {grade}");
+                    Console.WriteLine();
+                }
+
 
                 // 5. 显示排名（简化版）
                 Console.WriteLine("\n5. 平均分最高的学生:");
                 // TODO: 调用GetTopStudents(1)方法显示第一名
-
+                var top = scoreManager.GetTopStudents(1).First();
+                Console.WriteLine($"第一名: 学号: {top.StudentId}, 平均分: {top.Average}");
+
+
 
                 // 6. 文件操作
                 Console.WriteLine("\n6. 数据持久化演示:");
                 // TODO: 保存和读取学生文件
-
+                string filePath = "students.csv";
+                dataManager.SaveStudentsToFile(studentManager.GetAll(), filePath);
+                var loadedStudents = dataManager.LoadStudentsFromFile(filePath);
+                Console.WriteLine("读取到的学生信息:");
+                foreach (var student in loadedStudents)
+                {
+                    Console.WriteLine(student);
+                }
 
             }
             catch (Exception ex)