The next stage is to actually run your executable program. To run an executable in UNIX, you simply type the name of the file containing it, in this case program (or a.out)
This executes your program, printing any results to the screen. At this stage there may be run-time errors, such as division by zero, or it may become evident that the program has produced incorrect output.
If so, you must return to edit your program source, and recompile it, and run it again.