tftp客户端程序，解决了原tftp1.0客户端代码传输中大约128k字节应答计数有问题的bug，已在windows环境下进行测试，可以使用。(TFTP client program, to solve the original tftp1.0 client code transmission, about 128K bytes, answer count problems bug, has been tested in the windows environment, you can use.)