逻辑函数化简，参考了 清华大学的《数字逻辑与数字集成电路》这本书里面的化简方法，并把它的化简方法用C++语言实现。里面用两个C++类实现-Logic function simplification, reference to Tsinghua University, digital logic and digital integrated circuits, the book inside the simplified method, and its simplification metho