SUB iterate
    iter = 0
    phi0 = 1!
    DO
        phi1 = 1! + (1! / phi0)
        diff = ABS(phi1 - phi0)
        phi0 = phi1
        iter = iter + 1
    LOOP UNTIL (.00001 > diff)

    PRINT "Result: "; phi1; " after "; iter; " iterations"
    PRINT "The error is approximately "; phi1 - (.5 * (1! + SQR(5!)))
END SUB

CALL iterate
END