PROGRAM newton;

CONST
    epsilon = 1e-6;

VAR
    number       : integer;
    root, sqroot : real;

BEGIN
    REPEAT
        writeln;
        write('Enter new number (0 to quit): ');
        read(number);

        IF number = 0 THEN BEGIN
            writeln(number:12, 0.0:12:6);
        END
        ELSE IF number < 0 THEN BEGIN
            writeln('*** ERROR:  number < 0');
        END
        ELSE BEGIN
            sqroot := sqrt(number);
            writeln(number:12, sqroot:12:6);
            writeln;

            root := 1;
            REPEAT
                root := (number/root + root)/2;
                writeln(root:24:6,
                        100*abs(root - sqroot)/sqroot:12:2,
                        '%')
            UNTIL abs(number/sqr(root) - 1) < epsilon;
        END
    UNTIL number = 0
END.