#include <GL/glut.h>

void init(float r, float g, float b){
	glClearColor(r,g,b,0.0); //set the background color
	glMatrixMode(GL_PROJECTION);
	gluOrtho2D(0.0,20,0.0,20);//x from 0 to 200, y from 0 to 200
}

void segment(void){
	
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(1.0,1.0,1.0); //color of point
	//float x[5],y[5];
	//scanf("%f %f", &x1, &y1);
	//scanf("%f %f", &x2, &y2);
	float x[] = {8,2,11,6,5,4,12,9,6,1};
	float y[] = {3,10,3,6,8,12,1,4,9,14};
	int i,n = 10;
	float sumx = 0,sumy = 0;
	
	for(i = 0; i < n; i++){
		sumx += x[i];
		sumy += y[i];
	}
	
	float barx = sumx / n;
	float bary = sumy / n;
	float xy[n], sumxy = 0;
	float sqx = 0;
	float xx,yy;
	
	for(i = 0; i < n; i++){
		xx = x[i] - barx;
		yy = y[i] - bary;
		xy[i] = xx*yy;
		sumxy += xy[i];
		sqx += xx*xx;
	}

	float slop = sumxy / sqx;
	float c = bary-slop*barx;
	float barx1 = 110;

	float bary1 = slop * barx1 + c;

	glBegin(GL_POINTS);

		for(i = 0; i < n; i++){
			glVertex2i(x[i],y[i]);
		}
	glEnd();

	glBegin(GL_LINES);
	//	for(i = 0; i < n; i++){
	//		glVertex2i(x[i],y[i]);
	//	}
		//glVertex2i(barx,bary); // co-ordinates of point
		glVertex2i(barx1,bary1); // co-ordinates of point
		glVertex2i(barx,bary); // co-ordinates of point
	glEnd();

	glFlush();
}

void main(int argc, int *argv[]){

	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // GLUT_RGB stands for OpenGL Utility and RGB for red,green,blue
	glutInitWindowSize(500, 500); //Inbuilt func to set the size of window
	glutInitWindowPosition(250, 200);//inbuilt func to put the output window at position
	glutCreateWindow("GCV Assignment 1 Que 5");	//Title of Window
	init(0.0,0.0,0.0); //Function Called For background colors RGB respectively, vary between 0.0to 1.0 to  see the differn background colors
	glutDisplayFunc(segment); //function called segment
	glutMainLoop();
}