：本实验实现一般检索式变换成逆波兰表达式。变换过程就是根据，将检索运算符排在需要运算的两个检索词之后，以形成逆波兰变换式。-: In this experiment, the realization of the general retrieval style transformation into a Reverse Polish expressions. Transformation process is based on the search operator in the needs o