From eea86f1c62567be8c00202367e9a401555a0f5f9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E8=B5=B5=E6=99=AF=E8=A8=80?= <1373241747@qq.com> Date: Wed, 13 Aug 2025 17:44:18 +0800 Subject: [PATCH] =?UTF-8?q?CSharp=5F=E8=B5=B5=E6=99=AF=E8=A8=80=5F?= =?UTF-8?q?=E7=AC=83=E5=AE=9E45?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- Program.cs | 364 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 364 insertions(+) create mode 100644 Program.cs diff --git a/Program.cs b/Program.cs new file mode 100644 index 0000000..e3a5d22 --- /dev/null +++ b/Program.cs @@ -0,0 +1,364 @@ +using System; +using System.Collections.Generic; +using System.IO; + +namespace StudentManagementSystem +{ + // 成绩等级枚举 + public enum Grade + { + F = 0, + D = 60, + C = 70, + B = 80, + A = 90 + } + + // 泛型仓储接口 + public interface IRepository + { + void Add(T item); + bool Remove(T item); + List GetAll(); + List Find(Func predicate); + } + + // 学生类 + public class Student : IComparable + { + public string StudentId { get; private set; } + public string Name { get; private set; } + public int Age { get; private set; } + public Student(string studentId, string name, int age) + { + 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) throw new ArgumentOutOfRangeException("年龄不能为负数"); + + StudentId = studentId; + Name = name; + Age = age; + } + public override string ToString() + { + return $"学号: {StudentId}, 姓名: {Name}, 年龄: {Age}"; + } + + + public int CompareTo(Student? other) + { + if (other == null) return 1; // 如果other为null，当前对象排在前面 + return string.Compare(StudentId, other.StudentId, StringComparison.Ordinal); + + } + + public override bool Equals(object? obj) + { + return obj is Student student && StudentId == student.StudentId; + } + public override int GetHashCode() + { + return StudentId?.GetHashCode() ?? 0; + } + } + // 成绩类 + public class Score + { + public string Subject { get; private set; } + public double Points { get; private set; } + + public Score(string subject, double points) + { + if (string.IsNullOrWhiteSpace(subject)) throw new ArgumentException("科目不能为空"); + if (points < 0 || points > 100) throw new ArgumentOutOfRangeException("成绩必须在0到100之间"); + Subject = subject; + Points = points; + } + + + + public override string ToString() + { + return $"科目: {Subject}, 成绩: {Points:F2}"; // 格式化成绩到小数点后两位 + } + } + + // 学生管理类 + public class StudentManager : IRepository + { + private List students = new List(); + + + public void Add(Student item) + { + if (item == null) throw new ArgumentNullException(nameof(item), "学生信息不能为空"); + if (students.Contains(item)) throw new InvalidOperationException("学生已存在"); + students.Add(item); + students.Sort(); // 保持学生列表按学号排序 + } + public bool Remove(Student item) + { + if (item == null) throw new ArgumentNullException(nameof(item), "学生信息不能为空"); + if (!students.Contains(item)) throw new InvalidOperationException("学生不存在"); + return students.Remove(item); + } + public List GetAll() + { + return new List(students); + } + public List Find(Func predicate) + { + if (predicate == null) throw new ArgumentNullException(nameof(predicate), "查询条件不能为空"); + 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) + { + if (minAge < 0 || maxAge < 0) throw new ArgumentOutOfRangeException("年龄不能为负数"); + if (minAge > maxAge) throw new ArgumentException("最小年龄不能大于最大年龄"); + List result = new List(); + foreach (var student in students) + { + if (student.Age >= minAge && student.Age <= maxAge) + { + result.Add(student); + } + } + return result; + } + } + + + // 成绩管理类 + public class ScoreManager + { + private Dictionary> scores = new Dictionary>(); + public void AddScore(string studentId, Score score) + { + if (string.IsNullOrWhiteSpace(studentId)) throw new ArgumentException("学号不能为空"); + if (score == 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) + { + + if (string.IsNullOrWhiteSpace(studentId)) throw new ArgumentException("学号不能为空"); + if (scores.ContainsKey(studentId)) + { + return new List(scores[studentId]); + } + return new List(); + } + + public double CalculateAverage(string studentId) + { + if (string.IsNullOrWhiteSpace(studentId)) throw new ArgumentException("学号不能为空"); + if (!scores.ContainsKey(studentId) || scores[studentId].Count == 0) return 0.0; + double total = 0.0; + int count = 0; + foreach (var score in scores[studentId]) + { + total += score.Points; + count++; + } + return total / count; + } + + public Grade GetGrade(double score) + { + if (score < 0 || score > 100) throw new ArgumentOutOfRangeException("成绩必须在0到100之间"); + 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 kvp in scores) + { + double avg = CalculateAverage(kvp.Key); + averages.Add((kvp.Key, avg)); + } + averages.Sort((a, b) => b.Average.CompareTo(a.Average)); // 按平均分降序排序 + return averages.GetRange(0, Math.Min(count, averages.Count)); + } + + public Dictionary> GetAllScores() + { + return new Dictionary>(scores); + } + } + + // 数据管理类 + public class DataManager + { + public void SaveStudentsToFile(List students, string filePath) + { + // TODO: 实现保存学生数据到文件 + // 提示：使用StreamWriter，格式为CSV + 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}"); + } + } + Console.WriteLine("学生数据已保存到文件"); + } + catch (Exception ex) + { + Console.WriteLine($"保存文件时发生错误: {ex.Message}"); + } + } + public List LoadStudentsFromFile(string filePath) + { + List students = new List(); + // TODO: 实现从文件读取学生数据 + // 提示：使用StreamReader，解析CSV格式 + try + { + // 在这里实现文件读取逻辑 + using (var reader = new StreamReader(filePath)) + { + string headerLine = reader.ReadLine(); // 读取并忽略标题行 + string line; + while ((line = reader.ReadLine()) != null) + { + var parts = line.Split(','); + if (parts.Length == 3) + { + string studentId = parts[0]; + string name = parts[1]; + if (int.TryParse(parts[2], out int age)) + { + students.Add(new Student(studentId, name, age)); + } + } + } + } + Console.WriteLine("学生数据已从文件加载"); + return students; + } + catch (Exception ex) + { + Console.WriteLine($"读取文件时发生错误: {ex.Message}"); + } + return students; + } + } + + // 主程序 + class Program + { + static void Main(string[] args) + { + Console.WriteLine("=== 学生成绩管理系统 ===\n"); + // 创建管理器实例 + var studentManager = new StudentManager(); + var scoreManager = new ScoreManager(); + var dataManager = new DataManager(); + try + { + // 1. 学生数据（共3个学生） + Console.WriteLine("1. 添加学生信息:"); + studentManager.Add(new Student("2021001", "张三", 20)); + studentManager.Add(new Student("2021002", "李四", 19)); + studentManager.Add(new Student("2021003", "王五", 21)); + Console.WriteLine("学生信息添加完成"); + + // 2. 成绩数据（每个学生各2门课程） + Console.WriteLine("\n2. 添加成绩信息:"); + scoreManager.AddScore("2021001", new Score("数学", 95.5)); + scoreManager.AddScore("2021001", new Score("英语", 87.0)); + scoreManager.AddScore("2021002", new Score("数学", 78.5)); + scoreManager.AddScore("2021002", new Score("英语", 85.5)); + scoreManager.AddScore("2021003", new Score("数学", 88.0)); + scoreManager.AddScore("2021003", new Score("英语", 92.0)); + Console.WriteLine("成绩信息添加完成"); + + // 3. 测试年龄范围查询 + Console.WriteLine("\n3. 查找年龄在19-20岁的学生:"); + var ageFilteredStudents = studentManager.GetStudentsByAge(19, 20); + foreach (var student in ageFilteredStudents) + { + 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($"\n学生: {student}"); + Console.WriteLine("成绩:"); + foreach (var score in scores) + { + Console.WriteLine($" {score}"); + } + Console.WriteLine($"平均分: {average:F2}, 等级: {grade}"); + } + + // 5. 显示排名（简化版） + Console.WriteLine("\n5. 平均分最高的学生:"); + // TODO: 调用GetTopStudents(1)方法显示第一名 + var topStudents = scoreManager.GetTopStudents(1); + foreach (var (StudentId, Average) in topStudents) + { + var student = allStudents.Find(s => s.StudentId == StudentId); + if (student != null) + { + Console.WriteLine($"第一名: {student}, 平均分: {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); + var loadedStudents = dataManager.LoadStudentsFromFile(filePath); + Console.WriteLine("从文件加载的学生信息:"); + foreach (var student in loadedStudents) + { + Console.WriteLine(student); + } + } + catch (Exception ex) + { + Console.WriteLine($"程序执行过程中发生错误: {ex.Message}"); + } + Console.WriteLine("\n程序执行完毕，按任意键退出..."); + Console.ReadKey(); + } + } +} \ No newline at end of file