using System;

​

​

​

public class Program

{

    public static void Main()

    {

        int choice;

        Console.WriteLine("Choose a method: \n1. Positive/Negative \n2. Pyramid \n3. f(x) = x^4+x^3-7x^2-x+6 \n4. Big or Small");

        choice = int.Parse(Console.ReadLine());

        while(true)

        {

            if(choice == 1)

            {

                Posnev();

                break;

            }

​

            else if(choice == 2)

            {

                Pyramid();

                break;

            }

​

            else if(choice == 3)

            {

                Function();

                break;

            }

​

            else if(choice == 4)

            {

                BigSmall();

                break;

            }

​

            else

            {

                Console.WriteLine("That is not an option.");

                Console.WriteLine("Choose a method: \n1. Positive/Negative \n2. Pyramid \n3. f(x) = x^4+x^3-7x^2-x+6 \n4. Big or Small");

                choice = int.Parse(Console.ReadLine());

            }   

        }

    }

    public static void Function()

    {

        int x;

        Console.WriteLine("Enter a value for x");

        x = int.Parse(Console.ReadLine());

        if(((x*x*x*x)+(x*x*x)-(7*x*x)-x+6) == 0)

        {

            Console.WriteLine("The value " + x + " IS a root of the equation");

        }

        else

        {

            Console.WriteLine("The value " + x + " IS NOT a root of the equation");

        }

    }

    public static void BigSmall()

    {

        int num1, num2;

        Console.WriteLine("Enter two numbers:");

        num1 = int.Parse(Console.ReadLine());

        num2 = int.Parse(Console.ReadLine());

        if (num1<num2)

        {

            Console.WriteLine("the second number is bigger. the difference is " + (num2-num1) + "."); 

        }

        else if (num1>num2)

        {

            Console.WriteLine("the first number is bigger. the difference is " + (num1-num2) + "."); 

        }

        else

        {

            Console.WriteLine("The numbers are equal");

        }

    }

    public static void Pyramid()

    {

        Console.WriteLine("How big should the pyramid be?");

        int size = int.Parse(Console.ReadLine());

        int i, j;

        for(i = 1; i <= size; i++)

        {

            for(j = 1; j <= i; j++)

            {

                Console.Write("\\");

            }

            Console.WriteLine();

        }

        for(i = size; i >= 1; i--)

        {

            for(j = 1; j <= i; j++)

            {

                Console.Write("/");

            }

            Console.WriteLine();

        }

    }

    public static void Posnev()

    {

        int num;

        Console.WriteLine("Enter a number");

        num = int.Parse(Console.ReadLine());

        if(num > 0)

        {

            Console.WriteLine("Your number is positive");

        }

        else if(num < 0)

        {

            Console.WriteLine("Your number is negetive");

        }

        else

        {

            Console.WriteLine("Your number is 0");

        }

    }

}