// Dackral Phillips
// COMP 6700 - Software Process
// 7/9/2K1
// Assignment 4A

// This is a program to calculate Beta 1 and Beta O regressions on spoofed data
// Given to me by the great Dr. Umphress.  I decided to keep things simple and
// have 3 functions (yes I did actually do a little design on paper for this
// assignment) and store all the data in arrays.

// Necessary Included libraries:

#include <iostream.h>
#include <iomanip.h>
#include <math.h>
#include <strings.h>
#include <stdlib.h>

// Function declarations

   double beta1(int n, int x[10], int y[10], double xavg, double yavg);
   double beta0(double yavg, double b1, double xavg);

// Begin main program

   int main()
   {
   
   // Lets eat some memory!  Declare a whole bunch of variables.
   
      int i = 0;
   
      int n = 10;
   
      double test1xavg = 0;
      double test1yavg = 0;
   
      double test2xavg = 0;
      double test2yavg = 0;
   
      double test3xavg = 0;
      double test3yavg = 0;
   
      double test1b1 = 0;
      double test1b0 = 0;
   
      double test2b1 = 0;
      double test2b0 = 0;
   
      double test3b1 = 0;
      double test3b0 = 0;
   
      int x1[10] = {130, 650, 99, 150, 128, 302, 95, 945, 368, 961};
      int y1[10] = {163, 765, 141, 166, 137, 355, 136, 1206, 433, 1130};
      int x2[10] = {130, 650, 99, 150, 128, 302, 95, 945, 368, 961};
      int y2[10] = {186, 699, 132, 272, 291, 331, 190, 1890, 788, 1601};
      int x3[10] = {163, 765, 141, 166, 137, 355, 136, 1206, 433, 1130};
      int y3[10] = {186, 699, 132, 272, 291, 331, 190, 1890, 788, 1601};
   
      for (i = 0; i < 10; i++)
      {
         test1xavg = test1xavg + x1[i];
         test1yavg = test1yavg + y1[i];
      
         test2xavg = test2xavg + x2[i];
         test2yavg = test2yavg + y2[i];
      
         test3xavg = test3xavg + x3[i];
         test3yavg = test3yavg + y3[i];
      }
   
      test1xavg = test1xavg / n;
      test1yavg = test1yavg / n;
   
      test2xavg = test2xavg / n;
      test2yavg = test2yavg / n;
   
      test3xavg = test3xavg / n;
      test3yavg = test3yavg / n;
   
      test1b1 = beta1(n, x1, y1, test1xavg, test1yavg);
      test1b0 = beta0(test1yavg, test1b1, test1xavg);
   
      test2b1 = beta1(n, x2, y2, test2xavg, test2yavg);
      test2b0 = beta0(test2yavg, test2b1, test2xavg);
   
      test3b1 = beta1(n, x3, y3, test3xavg, test3yavg);
      test3b0 = beta0(test3yavg, test3b1, test3xavg);
   
      system("clear");
      cout << endl << endl << "Test \t\t  B0  \t\t B1" << endl
         <<"_____\t\t______\t\t______" << endl
         <<"  1  \t\t" << test1b0 << "\t" << test1b1 << endl   
         <<"  2  \t\t" << test2b0 << "\t" << test2b1 << endl
         <<"  3  \t\t" << test3b0 << "\t" << test3b1 << endl;
      return 0;
   }

   double beta1(int n, int x[10], int y[10], double xavg, double yavg)
   {
      int i = 0;
      double numerator = 0;
      double denominator = 0;
      double b1 = 0;
   
      for (i = 0; i < 10; i++)
      {
         numerator = numerator + (x[i] * y[i]);
         denominator = denominator + (x[i] * x[i]);
      }
   
      numerator = numerator - (n * (xavg * yavg));
      denominator = denominator - (n * (xavg * xavg));
   	   
      b1 = numerator / denominator;
   
      return b1;
   }

   double beta0(double yavg, double b1, double xavg)
   {
      double b0 = 0;
   
      b0 = yavg - (b1 * xavg);
   
      return b0;
   }