using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Aylin Nava");

        //Program that solves the equation f(x)=x^2 + 2x +3 in a range of x (x1,x2) given by the user. Print the expression for each value of x. Example:

        //given x = 2;

        // f(2) = (2)^2 + 2 * (2) + 3 = 11

        Console.WriteLine("Program that solves the equation f(x)=x^2 + 2x +3 in a range of x (x1,x2) given by the user.");

        Start:

        int P1=0,P2=0,P3=0,ccc=1;

        Console.WriteLine("-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/");      

        Console.WriteLine("Insert the value of x1: ");

        int x1 = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine("Insert the value of x2: ");

        int x2 = Convert.ToInt32(Console.ReadLine());

        if (x1 <= 0 | x1 > 31 | x2 <= 0 | x2 > 31 | x2 < x1)

        {

            Console.WriteLine("\nX-X-X-X-X-Incorrect value, please try again.-X-X-X-X-X");

            goto Start;

        }

        //for statement, equation solver

        for (int i = x1; i <= x2; i++)

        {

            Console.WriteLine("\nCalculating value #{0}: \n",ccc);

            // f(x) = (x)^2 + 2 * (x) + 3 = 

            Console.WriteLine("f(x) = (x)^2 + 2 * (x) + 3 ");

            //proceedure, stating each step

            Console.WriteLine("f({0}) = ({0})^2 + 2 * ({0}) + 3 ",x1);

            P1 = i*i;   

            Console.WriteLine("f({0}) = {1} + 2 * ({0}) + 3 ",x1,P1);

            P2 = 2*i;

            Console.WriteLine("f({0}) = {1} + {2} + 3 ",x1,P1,P2);

            P3 = P1+P2+3;

            //final step

            Console.WriteLine("f({0}) = {1}",x1,P3);

            //Console.WriteLine("{0} {1} {2}", x1, x2, i);

            //counters

            x1++;

            ccc++;

        }

        //main goto flag

        goto Start;

    }

}

​