Existence　and　uniqueness　of　solution　of　constitutive　integration　of　non-associative　plasticity　has　been　an　open　issue　until　it　was　partly　solved　in　Zheng　et　al.　(2020),　where　the　constitutive　integration　of　elastic-perfect　plasticity　is　reduced　to　a　Mixed　Complementarity　Problem　(MiCP),　a　special　case　of　finite-dimensional　variational　inequalities,　and　the　qualitative　properties　of　the　MiCP　have　been　well　established　even　for　non-smooth　yield　surfaces　and　non-associated　flow　rules.　The　algorithm　for　the　MiCP,　called　GSPC,　has　been　proved　globally　convergent.　In　order　to　handle　plasticity　with　hardening　and　softening　behaviors,　hardening　functions　are　deemed　the　same　position　as　stress　components.　In　this　way,　hardening/softening　plasticity　reduces　to　elastic-perfect　plasticity,　and　the　GSPC　is　ideally　suited　to　hardening/softening　plasticity　with　no　need　to　revise.　The　application　of　the　proposed　procedure　to　the　Modified　Cam-Clay　plasticity　is　demonstrated.　Comparisons　are　made　with　the　return　mapping　(R-M)　algorithm,　indicating　that　those　examples　causing　R-M　to　fail　to　converge　can　be　easily　solved　using　GSPC.　(C)　2022　Elsevier　B.V.　All　rights　reserved.