freopen 重定向至文件后恢复至终端

操作系统	标准输入输出设备
Windows	CON
Linux	/dev/tty

Windows

freopen("CON", "r", stdin);
freopen("CON", "w", stdout);

Linux

freopen("/dev/tty", "r", stdin);
freopen("/dev/tty", "w", stdout);