7.2 Translate each of these expressions into IR trees, but using the Ex, Nx, and Cx constructors as appropriate. In each case, just draw pictures of the trees; an Ex tree will be a Tree Exp, an Nx tree will be a Tree Stm, and a Cx tree will be a Stm with holes labeled true and false into which labels can later be placed. g. if a then b else c, where a is an integer variable (true if # 0). j. if a