If you just type test, it will run a program named test,
but it is not your program! As it turns out, there is a system program
called test.
To run you own program called test, you need to use the following
command:
./test
The . means this directory, and the / is just a separate
between the directory and filename. You need to use ./ for all
the programs that you create because the current directory is not in
the path where Linux searches for executable programs.
This program should behave the way we expect.