{(c) 2001 Emur http://emur.org}

program Speakerplayer;
uses crt;
var x: word;
    k: char;

BEGIN
textbackground(0);clrscr;
textcolor(lightgray);
writeln;
writeln('  Emuruv PC speaker player (20Hz-18kHz)');writeln;
writeln(#25:3,'   1Hz ... 1          ',#24,'   1Hz ... 7');
writeln(#25:3,'  10Hz ... 2          ',#24,'  10Hz ... 8');
writeln(#25:3,' 100Hz ... 3          ',#24,' 100Hz ... 9');
writeln(#25:3,' 500Hz ... 4          ',#24,' 500Hz ... 6');
writeln;
writeln(#26:3,' 500Hz ... 5          ',#29,'  stop ... 0');
writeln('                         '   ,#26,' konec ... Esc');
x:=500;
textcolor(15);
window(4,12,15,12);
textbackground(blue);clrscr;
gotoxy(3,1);write(x:5,' Hz');
repeat
k:=readkey;
case k of
  '7':     begin if x<=17999 then x:=x+1; end;
  '8',#72: begin if x<=17990 then x:=x+10; end;
  '9':     begin if x<=17900 then x:=x+100; end;
  '1':     begin if x>=21 then x:=x-1; end;
  '2',#80: begin if x>=30 then x:=x-10; end;
  '3':     begin if x>=120 then x:=x-100; end;
  '4',#75: begin if x>=520 then x:=x-500; end;
  '5':     x:=500;
  '6',#77: begin if x<=17500 then x:=x+500; end;
  #27:     begin nosound; halt(1); end;
  #13,'0','.': begin nosound; readkey; end;
  end;
sound(x);
gotoxy(3,1);write(x:5,' Hz');
until k=#27;
nosound;
END.