---
title: "What is Fragile class problem.?"  
description: "What is Fragile class problem.?"  
author: "Royce Roy"  
published: 2017-02-25  
updated: 2020-09-18  
canonical: https://www.mindstick.com/interview/23210/what-is-fragile-class-problem  
category: "c#"  
tags: ["c#"]  
reading_time: 2 minutes  

---

# What is Fragile class problem.?

Fragile class problem is a problem of object oriented programing. Suppose we have two class first class is the parent and second class is the child class. In the child class we have inherited the parent class and both have two overloaded function means have same method name.\

```
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks; namespace ConsoleApplication8{    class Program    {        static void Main(string[] args)        {            Child obj = new Child();            int i = 100;            obj.NumberNumeric(i);            double j = 100;            obj.NumberNumeric(j);        }    }    public class Parent    {        public virtual void NumberNumeric(int i)        {            Console.WriteLine("Parent Number Function");        }    }    public class Child : Parent    {        public void NumberNumeric(double i)        {            Console.WriteLine("Child Number Function");        }    }} 
```

**When we run this application we get unexpected result**

![What is Fragile class problem.?](data:image/png;base64,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) \

To overcome this problem we can make the class sealed. In the above example I have make parent class and child and in the child I have extended parent class then in the main make the instance of child.

## Answers

### Answer by Royce Roy

Fragile class problem is a problem of object oriented programing. Suppose we have two class first class is the parent and second class is the child class. In the child class we have inherited the parent class and both have two overloaded function means have same method name.\

```
using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks; namespace ConsoleApplication8{    class Program    {        static void Main(string[] args)        {            Child obj = new Child();            int i = 100;            obj.NumberNumeric(i);            double j = 100;            obj.NumberNumeric(j);        }    }    public class Parent    {        public virtual void NumberNumeric(int i)        {            Console.WriteLine("Parent Number Function");        }    }    public class Child : Parent    {        public void NumberNumeric(double i)        {            Console.WriteLine("Child Number Function");        }    }} 
```

**When we run this application we get unexpected result**

![What is Fragile class problem.?](data:image/png;base64,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) \

To overcome this problem we can make the class sealed. In the above example I have make parent class and child and in the child I have extended parent class then in the main make the instance of child.


---

Original Source: https://www.mindstick.com/interview/23210/what-is-fragile-class-problem

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