Styjun

I am trying to store the elements that are given in the main function into the list from textinput class and echo it out. The numeric input class is to filter the elements that are being stored to be of numeric values only. I want the output to be just 10 as the purpose of numeric input class is to filter out the letter 'a'. However, I got some errors such as end of file expected and missing "" and "". I checked if i had missed out some of these but i couldn't find any missing ones. Also, am I doing this right because I am new to the language and I need some advice on how to correct and improve it. Thank You.

EDIT: I have edited my code with the feedbacks that I have gotten and some new error messages appeared. Errors such as:-

The name 'add_char' does not exist in the current context.

The type or namespace name 'List<>' could not be found.

'TextInput' does not contain a definition for 'c' and no extension method 'c' accepting a first argument of type 'TextInput' could be found

EDIT2: So after importing the System.Collections.Generic and changing the list to protected, I encountered other errors as shown in the screenshot:-
Error Messages

Code:

using System;
using System.Collections.Generic;

public class TextInput 

 protected List<char> add_char = new List<char>();

 public void Add(char c)

 add_char.Add(c);

 

 public string GetValue() 

 for (add_char.size = 0; add_char.size < 400; add_char.size++)
 
 return c; 
 

 



public class NumericInput:TextInput

 public new void Add(char c)

 if(char.IsNumber(c)) 

 add_char.Add(c);

 else

 Console.WriteLine("This is not a number");

 

 



public class UserInput

 public static void Main(string[] args)
 
 TextInput input = new NumericInput();
 input.Add('1');
 input.Add('a');
 input.Add('0');
 Console.WriteLine(input.GetValue());
 

This line prevents it from being added to list as char is never is a int (char and int are different types):

if(GetValue(this.c).GetType() == typeof(int)){

instead change it to:

if(char.IsNumber(c)) add_char.Add(c);

The name 'add_char' does not exist in the current context.

Because it doesn't. add_char is a local variable declared in the Add method of your TextInput class. Local variables can only be used in the method scope in which they're declared. You're trying to use it in a different method (the Add method of your NumericInput class). Perhaps you meant to declare it at the class level in TextInput?:

protected List<char> add_char = new List<char>();

public void Add(char c)

 //...

The type or namespace name 'List<>' could not be found.

Add using System.Collections.Generic; at the top of the file. Note also that Visual Studio helps you with this. If you place your cursor or hover your mouse in the use of List<> then a tooltip should show (with a little light bulb) to help correct the error.

'TextInput' does not contain a definition for 'c' and no extension method 'c' accepting a first argument of type 'TextInput' could be found

Because it doesn't. c is a local variable declared in the Add method of your TextInput class. Local variables can only be used in the method scope in which they're declared. When someone calls GetValue(), what exactly are you wanting to return? That method has no variables. With the above change you can move add_char to the class level, then that method can access it.