用普里姆(Prim)算法构造最小生成树；图的DFS算法的非递归遍历函数-She (Prim) algorithm to construct minimum spanning tree

此程序使用最小生成树Prim算法,用户输入图的输入文件名,程序读此文件(This procedure using minimum spanning tree Prim algorithm, user input figure input file name, program to read this file)

Plur algorithm constructs minimal spanning tree()