program biseccion;

 uses

  crt;

 var

   p, a, b, c, n : real;

   cc, ca, cb, resultado, resul : real;

   error, cont, l : integer;

   sal : boolean;



 function calculo(a : real) : real;

 begin

     calculo := cos(a) / a;

 end;



 function dato(x, y : integer) : integer;

 var

   tec : char;

   pos : integer;

   tex : string[5];

   valo : integer;

 begin

    dato := 0;

    fillchar(tex,6,' ');

    tex[0] := chr(5);

    pos := 1;

    gotoxy(x,y);

  repeat

     tec := readkey;

     if tec in[#48..#57] then

     begin

        tex[pos] := tec;

        tex[0] := chr(pos);

        gotoxy(x + pos,y);write(tex[pos]);

        pos := pos + 1;

        if pos > 5 then

        pos := 5;

     end;

     if tec = #8 then

     begin

         pos := pos - 1;

         if pos < 1 then

         pos := 1;

         tex[pos] := ' ';

        tex[0] := chr(pos);

        gotoxy(x + pos,y);write(tex[pos]);

     end;

  until (tec = #13) or (tec = #27);

  if tec = #27 then

  sal := true;

  if tec = #13 then

  begin

     val(tex,valo,error);

     dato := valo;

  end;

 end;



  procedure entrada_datos;

  begin

      gotoxy(10,1);write('<<< Programa De biseccion >>>');

      gotoxy(10,3);write('*** Entre los Datos ***');

      gotoxy(10,4);write('Valor de A = ','     ','Primer Valor');

      gotoxy(10,5);write('Valor de B = ','     ','Segundo Valor');

      gotoxy(10,6);write('Valor de p = ','     ','Veces de Intentos');

    a := dato(22,4);

    if sal = false then

    b := dato(22,5);

    if sal = false then

    p := dato(22,6);

  end;



  procedure calculamos;

  begin

      clrscr;

      entrada_datos;

      c := (a + b) / 2;

      cc := calculo(c);

      cont := 0;

    repeat

       n := b - c;

      if (abs(n) < p) or (cc = 0.0) then

      resultado := c

  else

    begin

       cc := calculo(c);

       cb := calculo(b);

       resul := cb * cc;

    if (resul < 0.0) then

     a := c

  else

     b := c

  end;

    cont := cont + 1;

    gotoxy(10,8);write(' Intentos : ',cont,'  Salio : ',c);

    c := (a + b) / 2;

  until (abs(n) < p) or (cc = 0.0);

  gotoxy(10,10);write(' El Resultado Es : ',resultado : 8:8);

  end;



  begin

     clrscr;

     calculamos;

     readln;

 end.