(* Name:Chong Tsz Hang *)
(* Class: 4E ** No: 25 *)
(* Assignment #1 ** Q.1 *)
(* Variable : first point coordinate: (x, y) ,
							second point coordinate: (a, b),
							slope of two points: slope *)
program slope1;
uses crt;
var
	 x, y, a, b: integer;
	 slope: real;
begin
	 clrscr;
	 write('Enter the first point (X, Y): ');
	 readln(x, y);
	 write('Enter the second point (A, B): ');
	 readln(a, b);
	 If x <> a
			then begin
							slope:= (y - b) / (x - a);
							writeln('The slope of the two points is: ',slope:4:1);
					 end
			Else writeln('The line is vertical.')
End.