以下 c# 代码中属性成人的堆栈溢出异常

Question

The code is for taking the input from user such as their name and date of birth and return details as name and their age and whether they are child or not

Apart from the Adult property the rest of the code works fine

using System;
using System.IO;

public class Person
{
    //Fill code here
    private string firstName;
    private string lastName;
    private DateTime dob;
    //private string adult;

    public string FirstName
    {
        set { firstName = value; }
        get { return firstName; }
    }

    public string LastName
    {
        set { lastName = value; }
        get { return lastName; }
    }

    public DateTime Dob
    {
        set { dob = value; }
        get { return dob; }
    }
}

In the below property it has to check age and return "Adult" if the age is above or equal to 18 else "Child".

And according to the question i cannot declare the field for this.

public string Adult
{
    get
    {
        return Adult;
        throw (stackoverflow)
    }
    set
    {
        if (GetAge(dob) >= 18)
        {
            Adult = "Adult";
        }
        else
        {
            Adult = "Child";
        }
    }
}

Help me with the corrections needed for the above property so that it does not throw any exceptions and the reason why it throws the exception

public void DisplayDetails()
{
    Console.WriteLine("First Name: {0}", firstName);
    Console.WriteLine("Last Name: {0}", lastName);
    int age = GetAge(dob);
    Console.WriteLine("Age: {0}",age);
    Console.WriteLine(Adult);
    }
    
    public int GetAge(DateTime dob)
    {
        int age = 0;
        age = DateTime.Now.Year - dob.Year;
        return age;    
    }
}

public class Program
{
    public static void Main(String[] args)
    {
        //Fill code here
        Person p = new Person();
        Console.WriteLine("Enter first name");
        p.FirstName = Console.ReadLine();
        Console.WriteLine("Enter last name");
        p.LastName = Console.ReadLine();
        Console.WriteLine("Enter date of birth in yyyy/mm/dd/ format");
        p.Dob = Convert.ToDateTime(Console.ReadLine());
        
        p.DisplayDetails();
    }
}

Answer 1

You have an Adult property, and inside that property you manually defined a getter and setter, but they both use exactly the same property instead of using a field like you do in your other properties.

Note that the fields used in your other properties have lowercase names, while the properties start with an Upper case letter (which means that they are separate entities).

So you did declare adult like this but have commented it out:

//private string adult;

So you need to first uncomment it, then use it in your getter & setter.

public string Adult
    {
        get
        {
            return adult;
        }  
        set
        {
            if (GetAge(dob) >= 18)
            {
                adult = "Adult";
            }
            else
            {
                adult = "Child";
            }
        }
    }

But this also doesn't make sense, as your setter is not using the value which you pass into it, So while this might work. it is not really the best way to do it. Instead just use the Getter to return if it is an adult or child each time.

 public string Adult
  {
        get
        {
            if (GetAge(dob) >= 18)
                     return "Adult";
            else
                return "Child";
        }
}

(You should also include handling in case dob value is not valid (eg default value)

BTW: It might be better to use an Enum rather than a string, or just a boolean indicating if it is an adult (true) or child (false).