说明：  a_star算法,A*（A-Star)算法是一种静态路网中求解最短路最有效算法。本工程实现了简单了a_star算法，并在vc6.0下直接编译通过。
(a_star algorithm, A* (A-Star) algorithm is a static network in the most efficient algorithm for solving the shortest path. The project achieved a simple a_star algorithm, and in vc6.0 directly compile.)