For unity,debug is easy:
Go to vs2013,press F5,back to unity editor and play,then you can trigger your breakpoints.You can stop debug by going back to vs2013 and press Shift+F5,and this will not stop unity editor.
But how can we do it for UE4?
If I go to vs2013,press F5,vs2013 will launch a UE4 peocess,go to UE4 editor and play,then I can trigger my breakpoints.But when I back to vs2013 stop debug,the UE4 process will stop also.