From 955f1c34ba9a4934ac3ced68f2547451129d42a5 Mon Sep 17 00:00:00 2001 From: yyyq266 Date: Sun, 31 Aug 2025 23:09:47 +0800 Subject: [PATCH] Update Program.cs --- Homework/Program.cs | 212 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 183 insertions(+), 29 deletions(-) diff --git a/Homework/Program.cs b/Homework/Program.cs index b728a41..f1b7e87 100644 --- a/Homework/Program.cs +++ b/Homework/Program.cs @@ -1,7 +1,8 @@ -// See https://aka.ms/new-console-template for more information +// See https://aka.ms/new-console-template for more information using System; using System.Collections.Generic; using System.IO; +using System.Linq; namespace StudentManagementSystem { @@ -9,7 +10,11 @@ namespace StudentManagementSystem 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 @@ -20,6 +25,10 @@ public interface IRepository // Remove(T item) 返回bool // GetAll() 返回List // Find(Func predicate) 返回List + void Add(T item); + bool Remove(T item); + List GetAll(); + List Find(Func predicate); } @@ -27,25 +36,37 @@ public interface IRepository public class Student : IComparable { // TODO: 定义字段 StudentId, Name, Age - + public string StudentId { get; } + public string Name { get; } + public int Age { get; } 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.IsNullOrWhiteSpace(studentId)) + throw new ArgumentException("学号不能为空",nameof(studentId)); + if (string.IsNullOrWhiteSpace(name)) + throw new ArgumentException("姓名不能为空", nameof(name)); + if(age <= 0) + throw new ArgumentException("年龄必须为正整数", nameof(age)); + + 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 is null) return 1; + return string.Compare(StudentId, other.StudentId, StringComparison.Ordinal); } public override bool Equals(object? obj) @@ -63,18 +84,25 @@ public override int GetHashCode() public class Score { // TODO: 定义字段 Subject, Points - - + public string Subject { get; } + public double Points { get; } + public Score(string subject, double points) { // TODO: 实现构造方法，包含参数验证 - + if(string .IsNullOrWhiteSpace(subject)) + throw new ArgumentException("科目不能为空", nameof(subject)); + if (points < 0 || points > 100) + throw new ArgumentOutOfRangeException(nameof(points), "成绩必须在0到100之间", nameof(points)); + + Subject = subject; + Points = points; } public override string ToString() { // TODO: 返回格式化的成绩信息 - + return $"科目: {Subject}, 分数: {Points}"; } } @@ -83,6 +111,7 @@ public class StudentManager : IRepository { // TODO: 定义私有字段存储学生列表 // 提示：使用List存储 + private readonly List _students = new(); public void Add(Student item) @@ -90,32 +119,53 @@ public void Add(Student item) // TODO: 实现添加学生的逻辑 // 1. 参数验证 // 2. 添加到列表 - + if(item is null) + throw new ArgumentNullException(nameof(item),"学生不能为空"); + if(_students.Any(s => s.StudentId == item.StudentId)) + throw new ArgumentException($"学号为{item.StudentId}的学生已存在",nameof(item)); + + _students.Add(item); } public bool Remove(Student item) { // TODO: 实现Remove方法 - + return _students.Remove(item); } public List GetAll() { // TODO: 返回学生列表的副本 - + return new List(_students); } public List Find(Func predicate) { // TODO: 使用foreach循环查找符合条件的学生 - + var result = new List(); + 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 GetStudentsByAge(int minAge, int maxAge) { // TODO: 使用foreach循环和if判断实现年龄范围查询 - + var result = new List(); + foreach (var student in _students) + { + if (student.Age >= minAge && student.Age <= maxAge) + { + result.Add(student); + } + } + return result; } } @@ -124,7 +174,7 @@ public class ScoreManager { // TODO: 定义私有字段存储成绩字典 // 提示：使用Dictionary>存储 - + private readonly Dictionary> _scores = new(); public void AddScore(string studentId, Score score) { @@ -132,38 +182,77 @@ public void AddScore(string studentId, Score score) // 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", nameof(studentId)); + if (score is null) + throw new ArgumentNullException(nameof(score), "成绩不能为空"); + + if (!_scores.ContainsKey(studentId)) + _scores[studentId] = new List(); + + _scores[studentId].Add(score); } public List GetStudentScores(string studentId) { // TODO: 获取指定学生的所有成绩 - + if (_scores.TryGetValue(studentId, out var studentScores)) + { + return new List(studentScores); + } + return new List(); } 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) { - + return score switch + { + >= 90 => Grade.A, + >= 80 => Grade.B, + >= 70 => Grade.C, + >= 60 => Grade.D, + _ => 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 averages = new List<(string StudentId, double Average)>(); + + foreach (var studentId in _scores.Keys) + { + double average = CalculateAverage(studentId); + averages.Add((studentId, average)); + } + + // 按平均分降序排序 + averages.Sort((a, b) => b.Average.CompareTo(a.Average)); + + // 取前count个 + return averages.Take(count).ToList(); } public Dictionary> GetAllScores() { - return new Dictionary>(scores); + return new Dictionary>(_scores); } } @@ -177,7 +266,14 @@ public void SaveStudentsToFile(List students, string filePath) try { // 在这里实现文件写入逻辑 - + using var writer = new StreamWriter(filePath); + + writer.WriteLine("StudentId,Name,Age"); + + foreach (var student in students) + { + writer.WriteLine($"{student.StudentId},{student.Name},{student.Age}"); + } } catch (Exception ex) { @@ -194,7 +290,33 @@ public List LoadStudentsFromFile(string filePath) try { // 在这里实现文件读取逻辑 - + if (!File.Exists(filePath)) + { + Console.WriteLine("文件不存在"); + return students; + } + + using var reader = new StreamReader(filePath); + // 跳过表头 + reader.ReadLine(); + + string? line; + while ((line = reader.ReadLine()) != null) + { + var parts = line.Split(','); + if (parts.Length == 3) + { + try + { + var student = new Student(parts[0], parts[1], int.Parse(parts[2])); + students.Add(student); + } + catch (Exception ex) + { + Console.WriteLine($"解析学生数据时出错: {ex.Message}"); + } + } + } } catch (Exception ex) { @@ -241,22 +363,54 @@ 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 studentsByAge = studentManager.GetStudentsByAge(19, 20); + foreach (var student in studentsByAge) + { + 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 - + var allStudents = studentManager.GetAll(); + foreach (var student in allStudents) + { + var scores = scoreManager.GetStudentScores(student.StudentId); + double average = scoreManager.CalculateAverage(student.StudentId); + Grade grade = scoreManager.GetGrade(average); + + Console.WriteLine($"{student.Name} 的成绩:"); + foreach (var score in scores) + { + Console.WriteLine($" {score}"); + } + Console.WriteLine($" 平均分: {average:F2}, 等级: {grade}"); + Console.WriteLine(); + } // 5. 显示排名（简化版） Console.WriteLine("\n5. 平均分最高的学生:"); // TODO: 调用GetTopStudents(1)方法显示第一名 - + var topStudents = scoreManager.GetTopStudents(1); + if (topStudents.Count > 0) + { + var topStudent = allStudents.First(s => s.StudentId == topStudents[0].StudentId); + Console.WriteLine($"{topStudent.Name} 平均分最高: {topStudents[0].Average:F2}"); + } // 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(allStudents, filePath); + Console.WriteLine("学生数据已保存到文件"); + + var loadedStudents = dataManager.LoadStudentsFromFile(filePath); + Console.WriteLine("从文件加载的学生数据:"); + foreach (var student in loadedStudents) + { + Console.WriteLine(student); + } } catch (Exception ex) @@ -268,4 +422,4 @@ static void Main(string[] args) Console.ReadKey(); } } -} \ No newline at end of file +}