PHP variables

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

class PHP
{
    static void Main()
    {
        string line = string.Empty;
        string currLine = Console.ReadLine();
        StringBuilder fullLine = new StringBuilder();

        while(currLine != "?>")
        {
            currLine = Regex.Replace(Console.ReadLine(), @"(//|#).*", "");
            fullLine.AppendLine(currLine);
        }

        line = fullLine.ToString();
        line = Regex.Replace(line, @"(/\*).*?(\*/)", "");
        HashSet<string> results = new HashSet<string>();

    Match variable = Regex.Match(line, @"([^\\])\$([a-zA-Z_](\w*)?)");
    while (variable.Success)
        {
        results.Add(variable.Groups[2].Value);
            variable = variable.NextMatch();
        }

        string[] print = new string[results.Count];
        for (int i = 0; i < results.Count; i++) print[i] = results.ElementAt(i);
        Printing (print);
    }

    static void Printing(string[] print)
    {
        Array.Sort<string>(print);
        Console.WriteLine(print.Length);
        List<string> notUpper = new List<string>();

    for(int i = 0; i < print.Length; i++)
        {
            if(!char.IsUpper(print[i][0]))
            {
                notUpper.Add(print[i]);
                continue;
            }
            Console.WriteLine(print[i]);
        }

    for (int i = 0; i < notUpper.Count; i++)
        {
            Console.WriteLine(notUpper[i]);
        }
    }
}