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CSharp_贾兴道_无48 #20

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166 changes: 134 additions & 32 deletions Homework/Program.cs
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Original file line number Diff line number Diff line change
@@ -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
Expand All @@ -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
Expand All @@ -20,32 +25,46 @@ public interface IRepository<T>
// 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 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)
Expand All @@ -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}";
}
}

Expand All @@ -83,39 +106,53 @@ 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

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 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<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

var result = new List<Student>();
foreach (var student in _students) {
if (student.age <= maxAge && student.age >= minAge)
{
result.Add(student);
}
}
return result;
}
}

Expand All @@ -124,46 +161,74 @@ 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("学生ID不能为空");
if (score == null) throw new ArgumentException(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

if (_scores.TryGetValue(studentId, out var scoreList))
return new List<Score>(scoreList);
return new List<Score>();
}

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<string, List<Score>> GetAllScores()
{
return new Dictionary<string, List<Score>>(scores);
return new Dictionary<string, List<Score>>(_scores);
}
}

Expand All @@ -177,7 +242,11 @@ public void SaveStudentsToFile(List<Student> 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)
{
Expand All @@ -188,13 +257,23 @@ public void SaveStudentsToFile(List<Student> students, string filePath)
public List<Student> LoadStudentsFromFile(string filePath)
{
List<Student> students = new List<Student>();

// 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)
{
Expand Down Expand Up @@ -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)
{
Expand Down