该程序用于计算二维地图中，各路段的长度（需要知道各路段顶点坐标，以及各点间联系），采用文件操作的形式(txt文本)。-The program is used to calculate 2 d maps, the length of each section (need to know the various sections of vertex coordinates, as well as contact between each point), in the form of file ope