About exit [0]

For details about exit [0]-general Linux technology-Linux programming and kernel, refer to the following. [I = s] This post was last edited by Shi fan

Test whether the parameters called by the script are correct.
############################### Start Script ###### #################################
1 E_WRONG_ARGS = 65
2 script_parameters = "-a-h-m-z"
3 #-a = all,-h = help, and so on.
4
5 if [$ #-ne $ Number_of_expected_args]
6 then
7 echo "Usage: 'basename $ 0' $ script_parameters"
8 # 'basename $ 0' is the script file name
9 exit $ E_WRONG_ARGS
10 fi

I would like to ask what is the meaning of exit in row 9th? Exit + number?
Appendix: what is the meaning of output in line 1?