(*                 Teresa Tong F.4AS 30               *)
(* to find the two roots of a quadratic equation *)

program FindingRealRoots (input, output);
uses wincrt;
var X1, X2 :real;
    A ,B ,C ,D:integer;
    tryagain :char;
begin
  repeat
  writeln('Please enter the coefficient of x square term:  ');
  readln(A);
  writeln('Please enter the coefficient of x term:  ');
  readln(B);
  writeln('Please enter the constant term:  ');
  readln(C);
  D :=B*B-4*A*C;
  
  if D<0 then
    writeln('This quadratic equation has no real roots.')
  else
  begin
  X1 :=(-B+SQRT(D))/(2*A);
  X2 :=(-B-SQRT(D))/(2*A);
  writeln('The roots of this quadratic equation are  ',X1:5:2,' and ',  X2:5:2)
  end;

writeln('Continue?(Y/N) ');
readln(tryagain);
writeln;
until(tryagain='N')or(tryagain='n');
writeln('Bye Bye!')
end.

-/-\-/-\-/-\-/-\-/-\-/-\-/-\-/-\-/-\-/--\--/-\-/-\-/-\-/-\-/-\-/-\-/-\-/-\-/-\-/-\-
e.g.
Please enter the coefficient of x square term:
5
Please enter the coefficient of x term:
-10
Please enter the constant term:
-40
the roots of this quadratic equation are   4.00 and -2.00
Continue?(Y/N)
Y 

Please enter the coefficient of x square term:
4
Please enter the coefficient of x term:
-2
Please enter the constant term:
-12
the roots of this quadratic equation are   2.00 and -1.50
Continue?(Y/N)
Y 

Please enter the coefficient of x square term:
8
Please enter the coefficient of x term:
5
Please enter the constant term:
9
This quadratic equation has no real roots.
Continue?(Y/N)
N

Bye Bye!