From a228578d8d48ef16e7606a9992ac60963ba08146 Mon Sep 17 00:00:00 2001 From: jxd Date: Fri, 8 Aug 2025 00:34:39 +0800 Subject: [PATCH] first --- Homework/Program.cs | 166 +++++++++++++++++++++++++++++++++++--------- 1 file changed, 134 insertions(+), 32 deletions(-) diff --git a/Homework/Program.cs b/Homework/Program.cs index b728a41..4560c85 100644 --- a/Homework/Program.cs +++ b/Homework/Program.cs @@ -1,6 +1,7 @@ // See https://aka.ms/new-console-template for more information using System; using System.Collections.Generic; +using System.Diagnostics.CodeAnalysis; using System.IO; 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 @@ -20,32 +25,46 @@ 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); } // 学生类 public class Student : IComparable { // TODO: 定义字段 StudentId, Name, Age - - + public string StudentId; + public string name; + public 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.IsNullOrWhiteSpace(studentId)) + throw new ArgumentException("学号不能为空！"); + if (string.IsNullOrWhiteSpace(name)) + throw new ArgumentException("姓名不能为空！"); + if (age < 0 || age > 120) + throw new ArgumentException("年龄无效！"); + this.StudentId = studentId; + this.name = name; + this.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 +82,22 @@ public override int GetHashCode() public class Score { // TODO: 定义字段 Subject, Points - - + public string Subject; + public double Points; + 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"); + if (points < 0 || points > 100) throw new ArgumentException("分数无效"); + this.Subject = subject; + this.Points = points; } public override string ToString() { // TODO: 返回格式化的成绩信息 - + return $"{Subject}:{Points}"; } } @@ -83,39 +106,53 @@ public class StudentManager : IRepository { // TODO: 定义私有字段存储学生列表 // 提示：使用List存储 - + List _students = new List(); 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 ArgumentException(nameof(item)); + if (_students.Contains(item)) throw new ArgumentException("学号已存在"); + _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 - + List 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 <= maxAge && student.age >= minAge) + { + result.Add(student); + } + } + return result; } } @@ -124,7 +161,7 @@ public class ScoreManager { // TODO: 定义私有字段存储成绩字典 // 提示：使用Dictionary>存储 - + private Dictionary> _scores = new Dictionary>(); public void AddScore(string studentId, Score score) { @@ -132,38 +169,66 @@ 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("学生ID不能为空"); + if (score == null) throw new ArgumentException(nameof(score)); + 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 scoreList)) + return new List(scoreList); + 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 - + if (!_scores.ContainsKey(studentId) || !_scores[studentId].Any()) + return 0; + double total = 0; + foreach (var score in _scores[studentId]) + { + total += score.Points; + } + return total / _scores[studentId].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 average = new List<(string, double)>(); + foreach (var stu in _scores) + { + double avg = CalculateAverage(stu.Key); + average.Add((stu.Key, avg)); + } + return average; } public Dictionary> GetAllScores() { - return new Dictionary>(scores); + return new Dictionary>(_scores); } } @@ -177,7 +242,11 @@ public void SaveStudentsToFile(List students, string filePath) try { // 在这里实现文件写入逻辑 - + var writer = new StreamWriter(filePath); + foreach (var student in students) + { + writer.WriteLine($"{student.name},{student.StudentId},{student.age}"); + } } catch (Exception ex) { @@ -188,13 +257,23 @@ public void SaveStudentsToFile(List students, string filePath) public List LoadStudentsFromFile(string filePath) { List students = new List(); - // TODO: 实现从文件读取学生数据 // 提示：使用StreamReader，解析CSV格式 try { // 在这里实现文件读取逻辑 - + if (!File.Exists(filePath)) return students; + var reader = new StreamReader(filePath); + string? line; + while ((line = reader.ReadLine()) != null) + { + var part = line.Split(','); + if (line.Length != 3) continue; + if (int.TryParse(part[2], out int age)) + { + students.Add(new Student(part[0], part[1], age)); + } + } } catch (Exception ex) { @@ -241,23 +320,46 @@ 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 stu=studentManager.GetStudentsByAge(19, 20); + foreach (var result in stu) + { + Console.WriteLine(result); + } // 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($"{student.StudentId}"); + var score = scoreManager.GetStudentScores(student.StudentId); + foreach (var sc in score) + { + var grade = scoreManager.GetGrade(sc.Points); + Console.WriteLine($"{sc.Subject}:{sc.Points},{grade},"); + } + var avg = scoreManager.CalculateAverage(student.StudentId); + Console.WriteLine($"平均分:{avg}"); + } // 5. 显示排名（简化版） Console.WriteLine("\n5. 平均分最高的学生:"); // TODO: 调用GetTopStudents(1)方法显示第一名 - + var first = scoreManager.GetTopStudents(1); + if (first.Count != 0) + { + var top = first.First(); + var student = studentManager.Find(o => o.StudentId == top.StudentId).FirstOrDefault(); + Console.WriteLine($"{student!.name}:{student.StudentId}"); + Console.WriteLine($"{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 - - + dataManager.SaveStudentsToFile(studentManager.GetAll(), "students.txt"); + dataManager.LoadStudentsFromFile("students.txt"); } catch (Exception ex) {