  Some necessary and sufficient optimality conditions for inequality
constrained problems with continuously differentiable data were obtained in the
papers [I. Ginchev and V.I. Ivanov, Second-order optimality conditions for
problems with C$\sp{1}$ data, J. Math. Anal. Appl., v. 340, 2008, pp.
646--657], [V.I. Ivanov, Optimality conditions for an isolated minimum of order
two in C$\sp{1}$ constrained optimization, J. Math. Anal. Appl., v. 356, 2009,
pp. 30--41] and [V. I. Ivanov, Second- and first-order optimality conditions in
vector optimization, Internat. J. Inform. Technol. Decis. Making, 2014, DOI:
10.1142/S0219622014500540].
  In the present paper, we continue these investigations. We obtain some
necessary optimality conditions of Karush--Kuhn--Tucker type for scalar and
vector problems. A new second-order constraint qualification of Zangwill type
is introduced. It is applied in the optimality conditions.
