Metodo de Newton

{* paulogp *}
{* mac os 7 *}
program Ada28p;

uses
    MemTypes, QuickDraw, OSIntf;

var
    x, old_guess, new_guess: real;
    tecla: string;

begin
    repeat
        clearscreen;
        gotoxy(30, 2);
        writeln('Metodo de Newton');
        gotoxy(30, 3);
        writeln('~~~~~~');
        writeln;
        writeln;
        write('Insira o numero: ');
        readln(x);
        writeln;
        if x > 0.0 then
        begin
            new_guess:= x / 2;
            repeat
                old_guess:= new_guess;
                new_guess:= (old_guess + x / old_guess) / 2;
            until new_guess = old_guess;
            writeln('Raiz de ', x: 2, ' e ', new_guess: 3);
        end else
        if x = 0.0 then writeln('Raíz de ', x: 2, ' e ', x: 3) else
            writeln('Este programa funciona apenas com numeros positivos!');
        writeln;
        writeln;
        write('Repetir (s/n): ');
        readln(tecla);
        uprstring(tecla, true);
    until tecla = 'N';
end.