C#动物园项目：无法将用户输入的物种与年龄存入类字段

正在为学校项目开发一款动物园管理程序，可记录三个独立笼子中的3种动物（狮子Lion、熊Bear、狼Wolf），但目前无法将用户输入的数据存入各动物类对应字段。

要求创建3个实现IAnimal接口的类（Lion、Bear、Wolf），该接口包含2个属性（Species、Age）和2个方法（RequestUniqueCharacteristic、GetDescription）。

核心问题：程序能获取并存储动物的独特特征，但无法存储用户输入的物种（Species）和年龄（Age），调用GetDescription()方法时仅能输出独特特征。例如输出为："contains a 0-year-old with a red mane"，其中“old”和“with”之间的空白处应为物种名称。

现有代码 #

IAnimal接口 #

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Unity;

namespace TheZoo
{
    public interface IAnimal
    {
        public string Species { get; set; }
        public int Age { get; set; }

        public void RequestUniqueCharacteristic();

        public void GetDescription();
    }
}

Lion类 #

using Azure;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TheZoo
{
    internal class Lion:IAnimal
    {
        
        public string Species { get; set; }

        public int Age { get; set; }

        public string ManeColour { get; set; }

        public Lion()
        {

        }

        public Lion(int age, string species, string maneColour)
        {
            Species = species;
            Age = age;
            ManeColour = maneColour;
        }

        public void RequestUniqueCharacteristic()
        {
            
            Console.WriteLine("What colour is the Lions mane?");
            ManeColour = Console.ReadLine();
            
        }

        public void GetDescription()
        {
            Console.WriteLine($"contains a {Age}-year-old {Species} with a {ManeColour} mane.");
        }

    }
}

主程序代码 #

using Azure;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using TheZoo;

namespace TheZoo
{
    internal class Program
    {
        static void Main(string[] args)
        {
            //variable initialization
            string cage;
            string species;
            int age;

            //Created objects within a list
            List<IAnimal> list = new();
            Lion lion = new();
            Bear bear = new();
            Wolf wolf = new();

            list.Add(lion);
            list.Add(bear);
            list.Add(wolf);


            // Start of program, prompts user to input animal attributes
            for (int i = 1; i <= 3; i++)
            {
                cage = "Cage " + i;
                Console.WriteLine(cage);

                Console.WriteLine("What is the animals species? (Please capitalize the first letter)");
                species = Console.ReadLine();
                   
                if (species == "Lion" || species == "Bear" || species == "Wolf")
                {    
                    Console.WriteLine("How old is the animal?");
                    age = Convert.ToInt16(Console.ReadLine());  
                } 
                else
                {
                    Console.WriteLine("Please enter Lion, Bear, or Wolf with the first letter capitalized.");
                    Console.WriteLine("What is the animals species? (Please capitalize the first letter)");
                    species = Console.ReadLine();
                    Console.WriteLine("How old is the animal?");
                    age = Convert.ToInt32(Console.ReadLine());
                }

                if (species == "Lion")
                {
                    lion.RequestUniqueCharacteristic();
                    Console.WriteLine();
                }
                else if (species == "Bear")
                {
                    bear.RequestUniqueCharacteristic();
                    Console.WriteLine();
                }
                else if (species == "Wolf")
                {
                    wolf.RequestUniqueCharacteristic();
                    Console.WriteLine();
                }
                else
                {
                    Console.WriteLine("Something went wrong. Please try again.");
                }
            }

            Console.WriteLine("-----------------------------------");

            // Prints a summary from each class (Bear, Lion, Wolf)
            foreach (IAnimal animal in list)
            {
                animal.GetDescription();
            }
            Console.ReadLine();

            Console.WriteLine("Cages 1 - 3 have been updated.");
        }
    }
}

问题分析 #

主程序中，用户输入的species和age变量仅被临时存储，未赋值给对应动物对象的Species和Age属性，导致这些属性保持C#默认值（int类型默认0，string类型默认空字符串），最终输出异常。

解决步骤 #

1. 将输入值绑定到动物对象属性
   在判断物种的分支中，添加属性赋值代码，以Lion为例：

   if (species == "Lion")
   {
       lion.Age = age;
       lion.Species = species;
       lion.RequestUniqueCharacteristic();
       Console.WriteLine();
   }
   

   同理给Bear、Wolf的分支添加对应的Age和Species赋值逻辑。

2. 优化输入验证逻辑
   当前else分支仅重新输入一次，无法确保输入正确性，建议用循环强制用户输入合法内容：

   // 循环验证物种输入
   while (true)
   {
       Console.WriteLine("What is the animals species? (Please capitalize the first letter)");
       species = Console.ReadLine();
       if (species == "Lion" || species == "Bear" || species == "Wolf")
       {
           break;
       }
       Console.WriteLine("Invalid input! Please enter Lion, Bear, or Wolf with the first letter capitalized.");
   }
   
   // 循环验证年龄输入（确保是正整数）
   Console.WriteLine("How old is the animal?");
   while (!int.TryParse(Console.ReadLine(), out age) || age <= 0)
   {
       Console.WriteLine("Invalid age! Please enter a valid positive integer.");
   }
   

3. 可选：使用构造函数初始化对象
   若想简化属性赋值，可利用带参构造函数直接创建初始化完成的对象，调整主程序逻辑如下（以Lion为例）：

   // 先获取独特特征
   Console.WriteLine("What colour is the Lions mane?");
   string maneColour = Console.ReadLine();
   // 用构造函数创建已初始化的对象
   Lion lion = new Lion(age, species, maneColour);
   // 更新列表中的对象
   list[0] = lion;
   

内容的提问来源于stack exchange，提问作者TheStudentMans