Why my C# Code Checker method always returns true?

Alexander Svilarov

I am trying to do a program, that checks if a given .txt file, containing a C# code, has valid brackets.

When i paste a simple code like this:

if(true)
{
    Console.WriteLine("Hello");
}

My program says it is valid, which is true. But if i remove a bracket, like this:

if(true)
{
    Console.WriteLine("Hello");

It still says it's valid.

Here is my method for checking brackets:

static void CheckBrackets()
    {
        try
        {
            Console.Write("You file name (Default path is .....\\netcoreapp2.1\\): ");

            Console.ForegroundColor = ConsoleColor.Blue;
            string fileName = Console.ReadLine();

            Stack openingBrackets = new Stack();
            Queue closingBrackets = new Queue();

            using (StreamReader reader = new StreamReader(fileName))
            {
                bool check = true;
                string str = reader.ReadToEnd();
                char[] code = str.ToCharArray();

                foreach (char ch in code)
                {
                    if(ch == '(' || ch == '[' || ch == '{')
                    {
                        openingBrackets.Push(ch);
                    }
                    else if(ch == ')' || ch == ']' || ch == '}')
                    {
                        closingBrackets.Enqueue(ch);
                    }
                }

                while (openingBrackets.Count == 0 && closingBrackets.Count == 0)
                {
                    char currentOpeningBracket = (char)openingBrackets.Pop();
                    char currentClosingBracket = (char)closingBrackets.Dequeue();

                    if ((currentOpeningBracket == '(' && currentClosingBracket != ')')
                     || (currentOpeningBracket == '[' && currentClosingBracket != ']')
                     || (currentOpeningBracket == '{' && currentClosingBracket != '}'))
                    {
                        check = false;
                    }
                }

                if(check == true)
                {
                    Console.WriteLine("Valid.");
                }
                else
                {
                    Console.WriteLine("Not valid.");
                }
            }
        }
        catch (Exception exp)
        {
            ...
        }
    }

Any ideas why it doesn't work?

Giacomo Pirinoli

You should modify the while section of your code with this:

if (openingBrackets.Count != closingBrackets.Count)
{
    check = false;
}
else
{
    while (openingBrackets.Count > 0 && closingBrackets.Count > 0)
    {
        char currentOpeningBracket = (char)openingBrackets.Pop();
        char currentClosingBracket = (char)closingBrackets.Dequeue();

        if ((currentOpeningBracket == '(' && currentClosingBracket != ')')
        || (currentOpeningBracket == '[' && currentClosingBracket != ']')
        || (currentOpeningBracket == '{' && currentClosingBracket != '}'))
        {
            check = false;
        }
    }
}

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