complete the inquiry user info function
complete the declere of the user info function
add a function to show user info
add two declerations of function to read username
add a function to read user name
add a function to read nominate user name
add a function to get user name ;add a menu to select the method that get the user info
add a declaration of 'add user function'
add a function to add user
add a function to write new user infomation