matching parenthesis, C#

matching parenthesis

//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)
        {
            const char LeftParenthesis = '(';
        const char RightParenthesis = ')';
 
        static bool isBalancedWithStack(string str)
        {
 
            if (str.Length <= 1 || str.Equals(null))
                return false;
 
            var items = new Stack<int>(str.Length);
            int errorAt = -1;
            for (int i = 0; i < str.Length; i++)
            {
 
                if (str[i].Equals(LeftParenthesis))
                    items.Push(i);
                else if (str[i].Equals(RightParenthesis))
                {
                    if (items.Count == 0)
                    {
                        errorAt = i + 1;
                        return false;
                    }
                    items.Pop();
                }
            }
            if (items.Count > 0)
            {
                errorAt = items.Peek() + 1;
                return false;
            }
            return true;
        }
 
 
        static bool isBalancedWithoutStack(string str)
        {
 
            int count = 0;
 
            if (str.Length <= 1)
                return false;
 
            for (int i = 0; i < str.Length; i++)
            {
                if (str[i].Equals('('))
                    count++;
                else if (str[i].Equals(')'))
                {
                    count--;
                    if (count < 0)
                        return false;
                }
            }
 
            return (count == 0);
        }
 
        static bool checkParentheses(string str)
        {
            if (str.Length <= 1)
                return false;
 
            int count = 0;
 
            for (int i = 0; i < str.Length; i++)
            {
                switch (str[i])
                {
                    case '(':
                        count++;
                        break;
 
                    case ')':
                        count--;
                        if (count < 0)
                            return false;
                        break;
                }
            }
 
            return (count == 0);
 
        }
 
        public static void Main(string[] args)
        {
 
            string[] arrSample = new string[] { " ", "", "(", "()))))))", "(()((fff))())", "(()", "((((()))))", "(()(((())))())", "(()(((())))()", "()()()()()()()()()()()()" };
 
 
 
            for (int i = 0; i < arrSample.Length; i++)
            {
                if (isBalancedWithStack(arrSample[i]))
                {
                    Console.WriteLine("{0} is True", arrSample[i]);
                }
                else
                {
                    Console.WriteLine("{0} is False", arrSample[i]);
                }
 
                if (isBalancedWithoutStack(arrSample[i]))
                {
                    Console.WriteLine("{0} is True", arrSample[i]);
                }
                else
                {
                    Console.WriteLine("{0} is False", arrSample[i]);
                }
 
                if (checkParentheses(arrSample[i]))
                {
                    Console.WriteLine("{0} is True", arrSample[i]);
                }
                else
                {
                    Console.WriteLine("{0} is False", arrSample[i]);
                }
 
                Console.WriteLine();
            }
 
        }
    }
        }
    }
}


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