How can I cancel or skip a goal using actionlib, upon getting a keyboard input ?

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I am using simple_navigation_goal package for sending number of waypoints(say 6 waypoints) to the move_base. I am reading the goals from a .csv file and moving the robot to the goal one by one. But I need to skip/ cancel a goal, when I hit any key from he keyboard. I know that I have to use public member function cancelGoal () to achieve this.Could you please help me how can I achieve this by giving a sample code? Thanks