Explorer Diamond, C#

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//Title of this code
//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //Your code goes here
            int lines = 20;
            int halfLines = (lines / 2);
            int middleDashes = 1;
            
            //counter = w;
            
            Console.Write(Dashes(halfLines));
            Console.Write("*");
            Console.Write(Dashes(halfLines));
            Console.WriteLine();
            
            halfLines -= 1;
              
            for (int i = 0; i < lines/2; i++ )   
            {
                Console.Write(Dashes(halfLines));
                Console.Write("*");
                Console.Write(Dashes(middleDashes));
                Console.Write("*");
                
                middleDashes += 2;
                
                Console.Write(Dashes(halfLines));
                Console.WriteLine();
                
                halfLines -= 1;
            }
            
            //halfLines = 0;
            middleDashes -= 4;
            halfLines += 2;
             
            for (int i = 0; i < (lines/2 - 1); i++ )   
            {
                Console.Write(Dashes(halfLines));
                Console.Write("*");
                Console.Write(Dashes(middleDashes));
                Console.Write("*");
                
                middleDashes -= 2;
                
                Console.Write(Dashes(halfLines));
                Console.WriteLine();
                
                halfLines += 1;
            }
            
            halfLines = lines/2;
            
            Console.Write(Dashes(halfLines));
            Console.Write("*");
            Console.Write(Dashes(halfLines));
            Console.WriteLine();
            
        }
                    
            static string Stars(int n)
            {
                return new String('*', n);
            }
                    
            static string Dashes(int n)
            {
                return new String('-', n);
            }
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0.11 sec, absolute running time: 0.09 sec, cpu time: 0.09 sec, average memory usage: 16 Mb, average nr of threads: 4