对给出的任意一个合式公式（不超过四个命题变元），使学生会用C语言的语句表示出来，并且能够计算它在各组真值指派下所应有的真值。-Given any one of the well-formed formula (not more than four propositional variables), so that students will use C language statements that come out, and it is able to calculate the true