网络交换器查表过程仿真

任务及要求
编程模拟路由器查表过程，用(目的地址 掩码 下一跳)的IP路由表以及目的地址作为输入，为目的地址查找路由表，找出正确的下一跳并输出结果。

1. 建立一个路由表
   

   f=open(路由表.txt,r) list1=[] i=0 while(1): y=f.readline() if y==: break list1.append(y) f.close()

   while(1): z=input("目的IP地址：") x=z.split(.)

   for i in range(2,len(list1)):
       a=list1[i].split()
       q=a[1].split(.)
       e=a[2].split(.)
       if a[0]==1:
           if((int(x[0])&int(e[0])==int(q[0])) and (int(x[1])&int(e[1])==int(q[1])) and (int(x[2])&int(e[2])==int(q[2])) and (int(x[3])&int(e[3])==int(q[3]))):
               print("直接交付",a[3])
               break
            else:
               if ((int(x[0])&int(e[0])==int(q[0])) and (int(x[1])&int(e[1])==int(q[1])) and (int(x[2])&int(e[2])==int(q[2])) and (int(x[3])&int(e[3])==int(q[3]))):
                   print("间接交付，下一跳为：",a[3])
                   break
               else:
                   continue
       else:
           if ((int(x[0])&int(e[0])==int(q[0])) and (int(x[1])&int(e[1])==int(q[1])) and (int(x[2])&int(e[2])==int(q[2])) and (int(x[3])&int(e[3])==int(q[3]))):
               print(a[3])
               break
           else:
               print("转发分组出错！")
               break