I tried 3 tools before
If you do not have a cable, you will unable to unlock the ipad via itunes. But I tried to remove the password with the help of other tools:
This method will not erase your data, but it only applys to the device which is running ios 8 to ios 10.1
If you have your friend's Apple ID and password, you can use icloud to erase all the data, including the screen passcode.
3. third-party software
For myself, I used an ipad unlocker called joyoshare ipasscode unlocker to factory reset my device and became able to operated without password.