Linear Equation Details

clc
clear

% Filename: Rivera13p2
% Jeremy Rivera
% EGR 120-001
% User enters the coordinates of two points that are on a line, program calculates
%      the equation of a line,what type of line it is, and the slope

% VARIABLE DECLARATION
%      x1 (real) user input x coordinate of point 1
%      y1 (real) user input y coordinate of point 1
%      x2 (real) user input x coordinate of point 2
%      y2 (real) user input y coordinate of point 2
%      m  (real) slope of the line
%      b  (real) constant of the line
x1=input('Enter x coordinate of point 1: ');
y1=input('Enter y coordinate of point 1: ');
x2=input('Enter x coordinate of point 2: ');
y2=input('Enter y coordinate of point 2: ');
m=(y2-y1)/(x2-x1);
b=y1-m*x1;
if(x1==x2 && y1==y2)
fprintf('Error; same coordinates (%d, %d) cannot be used twice\n',x1,y1);
elseif
fprintf('Your two points (%d, %d) and (%d, %d) form a line\n',x1,y1,x2,y2);
elseif(b>=0)
fprintf('The equation of your line is: y = %.3fx + %.3f\n',m,b);
else
fprintf('The equation of your line is: y = %.3fx %.3f\n',m,b);
end
if(m==0)
fprintf('The equation of your line has a slope of 0\n',m);
elseif(m==Inf)
fprintf('The equation of your line has an undefined slope\n',m);
elseif(m==-Inf)
fprintf('The equation of your line has an undefined slope\n',m);
elseif(m==(y2-y1)/(x2-x1))
fprintf('The equation of your line has a slope of %.3f\n',m);
end
if(x1==x2 && y1==y2)
fprintf('Same coordinates cannot produce a line in the xy-plane\n');
elseif(y1==y2)
fprintf('The equation of your line is horizontal at y = %.3f\n',y1);
elseif(x1==x2)
fprintf('The equation of your line is vertical at x = %.3f\n',x1);
else
fprintf('The equation of your line is not horizontal nor vertical\n');
end