/*****************************************************************************
*       Outputs the slope, midpoint, length of a line between two points.    *
*       Inputed: [x1, y1], [x2, y2] (two points on the plane).               *
*       Outputed: slope, midpoint, length.                                   *
*       Written: October 18, 2001                                            *
*       By: Ronald Roberts                                                   *
*****************************************************************************/

//Program 25
//18OCT01
#include <iostream.h>
#include <iomanip.h>
#include <math.h>
int main()
{
/* declaration of variables */
double x1=0, x2=0, y1=0, y2=0, slope=0, mid1=0, mid2=0, length=0, b=0;

/* instructions and user input */
cout<<"This program computes slope, midpoint, and length"<<endl;
cout<<"The equation of a line equals y=mx+b where m=slope and b=y-intercept"<<endl;
cout<<"Please enter the first point(x,y):"<<endl;
cin>>x1>>y1;
cout<<"Please enter the second point(x,y):"<<endl;
cin>>x2>>y2;

/* calculation code */
if (x1==x2)
	{
		
		mid1=(x2+x1)/2;
		mid2=(y2-y1)/2;
		length=sqrt(pow((x2-x1), 2)+pow((y2-y1), 2));
		b=y1-slope*x1;
		cout<<"The slope is UNDEFINED OR NULL SET ."<<endl;
		cout<<"The midpoint is ("<<mid1<<", "<<mid2<<")."<<endl;
		cout<<"The length is "<<length<<" ."<<endl;
		cout<<"The equation is x="<<x1<<endl;
	}
else
	{
		slope=(y2-y1)/(x2-x1);
		mid1=(x2+x1)/2;
		mid2=(y2-y1)/2;
		length=sqrt(pow((x2-x1), 2)+pow((y2-y1), 2));
		b=y1-slope*x1;
		cout<<"The slope is "<<slope<<" ."<<endl;
		cout<<"The midpoint is ("<<mid1<<", "<<mid2<<")."<<endl;
		cout<<"The length is "<<length<<" ."<<endl;
		cout<<"The equation is y="<<slope<<"x+"<<b<<" ."<<endl;
	}
return 0;
}

/* OUTPUT
This program computes slope, midpoint, and length
The equation of a line equals y=mx+b where m=slope and b=y-intercept
Please enter the first point(x,y):
8
5
Please enter the second point(x,y):
8
-3
The slope is UNDEFINED OR NULL SET .
The midpoint is (8, -4).
The length is 8 .
The equation is x=8
*/