program _while;
uses crt;
const a  = 2.8;
      b  = -0.3;
      c  = 4;
      x0 = 0.8;
      xE = 2.8;
      h  = 0.2;
var
 x,y:double;

begin
 x:=x0;
 clrscr;
 while x<xE do begin
       if x<1.4 then y:=-1 else
       if x=1.4 then y:=0  else
       if x>1.4 then y:=1;
       writeln('x =',x:3:3,',  y =',y:3:3);
       x:=x+h;
 end;

 readln;
end.