Quadratic equation in Algol68

PROC print root = (INT ind, LONG COMPL x)VOID:
(   print(("x", ind, " := "));
    IF ABS(im OF x) < 1E-6 THEN
        print((re OF x, new line))
    ELSE print((x, new line))
    FI
);

main:
(   LONG COMPL a, b, c, d, x1, x2;
    print(("a := "));
    read((a));
    IF ABS a <1E-3 THEN
        print(( "Not a quadratic equation", new line));
        stop
    FI;
    print(("b := "));
    read((b));
    print(("c := "));
    read((c));

    a *:= 2;
    d := b*b-a*c*2.0;
    IF ABS d <1E-3 THEN
        print(("x := ", re OF (-b/a)))
    ELSE
        print root(1, (-b+long complex sqrt(d))/a);
        print root(2, (-b-long complex sqrt(d))/a)
    FI
)