program Triangle;

uses Crt;

var
   i : integer;
   side : array[1..3] of real;
begin
   clrscr;

{TITLE}
   writeln ('-----------------');
   writeln ('Triangle Analyser');
   writeln ('-----------------');
   writeln;
   writeln;
{INPUT}
   for i := 1 to 3 do
       begin
       write ('Please enter side number ', i,' of the Triangle: ');
       readln (side[i]);
       end;
   writeln;
   writeln;
{PROCESSING AND OUTPUT}
   if (side[1]+side[2]<=side[3]) or (side[2]+side[3]<=side[1])
   or (side[1]+side[3]<=side[2]) then {These conditions are invalid triangles}
      writeln('That triangle is invalid')
   else if (sqrt(sqr(side[1])+sqr(side[2])) = side[3])
   or (sqrt(sqr(side[1])+sqr(side[3])) = side[2])
   or (sqrt(sqr(side[2])+sqr(side[3])) = side[1]) then
      writeln('That triangle is right-angled')  {right angled <=> a^2+b^2=c^2}
   else if (side[1] = side[2]) and (side[2] = side[3]) then
      writeln('That triangle is equilateral')
   else if (side[1]=side[2]) or (side[2]=side[3]) or (side[1]=side[3]) then
      writeln('That triangle is isoceles')
   else writeln('That triangle is scalene'); {scalene = all sides different}
   writeln;
   writeln;
   writeln('Press any key to exit...');
   while not keypressed do;

end.