//Programmer: Teresa Dang

//Dates: (start/end) June 3-8

//Project: Greatest Common Factor

//Description: App that determines the largest common factor of two positive numbers given by the user. 

​

using System;

public class Program

{

    public static void Main()

    {

        double n1; //represents the first number given by the user

        double n2; //represents the second number given by the user

        double sNum; //represents the smaller number

        double lNum; //represents the larger number 

        double gcf; //represents the greatest common factor

        double R; //represents the remainder 

        Console.WriteLine("🧐 GREATEST COMMON FACTOR 🧐");

        Console.WriteLine(new String('-',40));

        Console.WriteLine("First Number: ");

        n1 = Convert.ToDouble(Console.ReadLine()); //retrieves the first number from the user

        Console.WriteLine("Second Number: ");

        n2 = Convert.ToDouble(Console.ReadLine()); //retrieves the second number from the user

        Console.WriteLine("\n");

        //CHECK FOR NEGATIVE NUMBERS

        while (n1 < 0 || n2 < 0){ //checks if any of the numbers given by the user are negative

            Console.WriteLine("Please re-enter two positive numbers.");

            Console.WriteLine("First Number: ");

            n1 = Convert.ToDouble(Console.ReadLine()); //retrieves the first number from the user

            Console.WriteLine("Second Number: ");

            n2 = Convert.ToDouble(Console.ReadLine());} //retrieves the second number from the user

            Console.WriteLine("\n");

        //ASSIGN USER INPUT NUMBERS

        if (n1<=n2){ //the first number is less than or equal to the second number

            sNum = n1; //classify the first number as the smallest number

            lNum = n2;} //classify the second number as the largest number

        else { //if first condition fails, then the second number is less than the first number

            sNum = n2; //classify the second number as the smallest number 

            lNum = n1;} //classify the first number as the largest number 

        R = lNum%sNum; //computes the remainder value

        //LOOP TO REASSIGN NUMBERS AND CALCULATE R... UNTIL R IS ZERO

        while (R!=0){ //remainder is not equal to zero

            sNum = R; //reassign the remainder as the smallest number

            lNum = sNum; //reassign the smallest number as the largest

            R = lNum%sNum;} //computes the remainder of the remainder divided by the smaller number

​

        gcf = sNum; //the greatest common factor is the smallest number

        Console.WriteLine("The greatest common factor of " + n1 + " and " + n2 + " is: " + gcf);        

    }

}