C# Online Compiler | .NET Fiddle

using System;

public class Program
{
	public static void Main()
	{
		IFile file1 = new FileInfo();
        FileInfo file2 = new FileInfo();
		
        file1.ReadFile(); 
        file1.WriteFile("content"); 
		
        file2.ReadFile(); 
        file2.WriteFile("content"); 
	}
}

interface IFile
{
    void ReadFile();
    void WriteFile(string text);
}

class FileInfo : IFile
{
    public void ReadFile()
    {
        Console.WriteLine("Reading File");
    }

    public void WriteFile(string text)
    {
        Console.WriteLine("Writing to file");
    }
}

 
using System;
​
public class Program
{
    public static void Main()
    {
        IFile file1 = new FileInfo();
        FileInfo file2 = new FileInfo();
        
        file1.ReadFile(); 
        file1.WriteFile("content"); 
        
        file2.ReadFile(); 
        file2.WriteFile("content"); 
    }
}
​
interface IFile
{
    void ReadFile();
    void WriteFile(string text);
}
​
class FileInfo : IFile
{
    public void ReadFile()
    {
        Console.WriteLine("Reading File");
    }
​
    public void WriteFile(string text)
    {
        Console.WriteLine("Writing to file");
    }
}
​
​

Compilation error (line 1, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 1, col 0): Syntax error.
Compilation error (line 2, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 2, col 0): Syntax error.
Compilation error (line 3, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 3, col 0): Syntax error.
Compilation error (line 4, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 4, col 0): Syntax error.
Compilation error (line 5, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 5, col 0): Syntax error.
Compilation error (line 6, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 6, col 0): Syntax error.
Compilation error (line 7, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 7, col 0): Syntax error.
Compilation error (line 8, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 8, col 0): Syntax error.
Compilation error (line 9, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 9, col 0): Syntax error.
Compilation error (line 10, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 10, col 0): Syntax error.
Compilation error (line 11, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 11, col 0): Syntax error.
Compilation error (line 12, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 12, col 0): Syntax error.
Compilation error (line 13, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 13, col 0): Syntax error.
Compilation error (line 14, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 14, col 0): Syntax error.
Compilation error (line 15, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 15, col 0): Syntax error.
Compilation error (line 16, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 16, col 0): Syntax error.
Compilation error (line 17, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 17, col 0): Syntax error.
Compilation error (line 18, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 18, col 0): Syntax error.
Compilation error (line 19, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 19, col 0): Syntax error.
Compilation error (line 20, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 20, col 0): Syntax error.
Compilation error (line 21, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 21, col 0): Syntax error.
Compilation error (line 22, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 22, col 0): Syntax error.
Compilation error (line 23, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 23, col 0): Syntax error.
Compilation error (line 24, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 24, col 0): Syntax error.
Compilation error (line 25, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 25, col 0): Syntax error.
Compilation error (line 26, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 26, col 0): Syntax error.
Compilation error (line 27, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 27, col 0): Syntax error.
Compilation error (line 28, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 28, col 0): Syntax error.
Compilation error (line 29, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 29, col 0): Syntax error.
Compilation error (line 30, col 0): Labels are not valid outside methods/multiline lambdas.
Compilation error (line 30, col 0): Syntax error.