Parenthesis C# Exercise - C# Programming Course

// Importing necessary namespace for handling collections
using System;  // Basic namespace for console input/output and fundamental operations
using System.Collections.Generic;  // For using the Stack class

class Program
{
    // Function to check if a sequence of parentheses is balanced
    static bool IsBalanced(string parentheses)
    {
        // Create a stack to hold the open parentheses
        Stack stack = new Stack();  // Stack will help to track unmatched open parentheses

        // Iterate through each character in the input string
        foreach (char ch in parentheses)  // For each character in the string
        {
            // If the character is an opening parenthesis, push it onto the stack
            if (ch == '(')  // If the character is an open parenthesis
            {
                stack.Push(ch);  // Add the open parenthesis to the stack
            }
            // If the character is a closing parenthesis, check if there's a matching open parenthesis
            else if (ch == ')')  // If the character is a closing parenthesis
            {
                // If the stack is empty, it means no matching open parenthesis, return false
                if (stack.Count == 0)  // If there are no open parentheses to match with
                {
                    return false;  // It means the parentheses are not balanced
                }
                stack.Pop();  // Remove the top item from the stack (matching the open parenthesis)
            }
        }

        // If the stack is empty, all open parentheses had matching closing parentheses
        return stack.Count == 0;  // If the stack is empty, the parentheses are balanced
    }

    // Main program method to test the IsBalanced function
    static void Main(string[] args)
    {
        // Test the IsBalanced function with valid and invalid examples
        string test1 = "(()()(()))";  // A valid sequence of parentheses
        string test2 = "(((()";  // An invalid sequence of parentheses

        // Display the results of the balance check
        Console.WriteLine($"Is the sequence '{test1}' balanced? {IsBalanced(test1)}");  // Expecting true
        Console.WriteLine($"Is the sequence '{test2}' balanced? {IsBalanced(test2)}");  // Expecting false
    }
}