构造函数在对象创建时打印文本。

huangapple
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英文:

Constructor prints text when object is created

问题

我在一个C#控制台应用程序中工作，正在学习面向对象编程。首先，我有一个Person类，

  1. class Person
  2. {
  3.     public string Name;
  4.     public string LastName;
  6.     public void Comment()
  7.     {
  8.         Console.WriteLine("来自Person类的评论");
  9.     }

和Student类

  1. class Student : Person
  2. {
  3.     public int IndexNr = 171124;
  4.     public int totalSubjects;
  5.  
  6.     public Student()
  7.     {
  8.         Console.WriteLine("索引号=" + IndexNr);
  9.     }
  10.     public Student(int subjectsTotal, int nr) 
  11.     {
  12.         totalSubjects = nr;
  13.         Console.WriteLine("平均成绩= " + subjectsTotal / totalSubjects);
  14.     }
  16.     public void Comment()
  17.     {
  18.         Console.WriteLine("来自Student类的评论");
  19.     }
  20. }

在Program.cs的Main函数中，代码如下：

  1. static void Main(string[] args)
  2. {
  3.     Console.WriteLine("学生信息");
  5.     Student st2 = new Student();
  6.     st2.Name = "name1";
  7.     st2.LastName = "lastname1";
  8.     Console.WriteLine("姓名=" + st2.Name + " 姓氏=" + st2.LastName);
  9.     Student st1 = new Student(90, 10);
  11.     //多态示例 -> 这里是我需要帮助的地方
  12.     Person p1 = new Person();
  13.     Person s1 = new Student();
  14.             
  15.     p1.Comment();
  16.     s1.Comment();
  17. }

所以，当我创建Person s1 = new Student()对象时，它只打印来自Person类的Comment函数，而不是来自Person和Student类的两个Comment函数。

我在Java中尝试了相同的操作，那里一切都运行得很好。您能告诉我我在哪里出错或者遗漏了什么吗？谢谢。

英文:

I am working in a C# console application and I am learning OOP.
First, I have a Person Class,

  1.    class Person
  2.    {
  3.     public string Name;
  4.     public string LastName;
  6.     public void Comment()
  7.     {
  8.         Console.WriteLine("Comment from Person Class");
  9.     }

and Student class

  1. class Student : Person
  2. {
  3.     public int IndexNr = 171124;
  4.     public int totalSubjects;
  6.     public Student()
  7.     {
  8.         Console.WriteLine("Index number=" + IndexNr);
  9.     }
  10.     public Student(int subjectsTotal,int nr) 
  11.     {
  12.         totalSubjects= nr;
  13.         Console.WriteLine("Average grade= " + subjectsTotal/ totalSubjects);
  14.     }
  16.     public void Comment()
  17.     {
  18.         Console.WriteLine("Comment from Student class");
  19.     }
  21. }

And in the Program.cs in the Main function the code goes like this:

  1.     static void Main(string[] args)
  2.     {
  4.         Console.WriteLine("Student Info");
  6.         Student st2= new Student();
  7.         st2.Name= "name1";
  8.         st2.LastName = "lastname1";
  9.         Console.WriteLine("Name=" + st2.Name+ " LastName=" + st2.LastName);
  10.         Student st1 = new Student(90,10);
  12.         //Polymorphism example -> here is where I need help
  13.         Person p1 =  new Person();
  14.         Person s1 = new Student();
  15.         
  17.         p1.Komenti();
  18.         s1.Komenti();
  20.     }

So, when I create Person s1 = new Student() object it prints out the the Comment function from only Person class, and not 1 from Person and 1 from Student class.

I have tried the same in Java as well and there it works very well.
Can you please tell me and enlighten me where am I making mistakes or what am I missing?
Thank you.

答案1

得分: 1

请尝试在Student类的Comment方法上使用override修饰符，以覆盖Person类的实现。您可以参考以下链接：https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/override 然后，这将覆盖person的实现。

  1. public class Student : Person
  2. {
  3.     public int IndexNr = 171124;
  4.     public int totalSubjects;
  6.     public Student()
  7.     {
  8.         Console.WriteLine("Index number=" + IndexNr);
  9.     }
  10.     public Student(int subjectsTotal, int nr) 
  11.     {
  12.         totalSubjects = nr;
  13.         Console.WriteLine("Average grade= " + subjectsTotal / totalSubjects);
  14.     }
  16.     public override void Comment()
  17.     {
  18.         Console.WriteLine("Comment from Student class");
  19.     }
  20. }
英文:

Try using the override modifier on the Comment method in the Student class https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/override This should then override the person implementation

  1. public class Student : Person
  2. {
  3.     public int IndexNr = 171124;
  4.     public int totalSubjects;
  6.     public Student()
  7.     {
  8.         Console.WriteLine("Index number=" + IndexNr);
  9.     }
  10.     public Student(int subjectsTotal,int nr) 
  11.     {
  12.         totalSubjects= nr;
  13.         Console.WriteLine("Average grade= " + subjectsTotal/ totalSubjects);
  14.     }
  16.     public override void Comment()
  17.     {
  18.         Console.WriteLine("Comment from Student class");
  19.     }
  21. }

huangapple
  • 本文由 发表于 2023年2月19日 05:42:27
  • 转载请务必保留本文链接：https://go.coder-hub.com/75496568.html
  • c#
  • oop
  • polymorphism
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