C++ :: How To Output From TXT File

So I have a .txt file with, Name >> Username >> password >> adminstatus. It is filled with various names. for e.g.

Bob bobby bob123 1
tim timmy tim123 1
rit ritty rit123 0
john johnny john123 0
mary maryy mary123 mary 1

1 will represent admin in the program and 0 will represent a normal user. I want to make part of the program do something like this. > If adminstatus = 1, discount rate =3%. The thing is I will be using UDF to do so and I am unsure of how I am going to read for each user. What I mean by this is. If tim logins, how do I read ONLY tims line's admin status.

Currently I have a Login UDF. for that UDF I return something I named Loginstatus. If the login status = 1 . It will run the current problem that I'm trying to solve which is displaying the user adminstatus's discount rate. So how am I suppose to display the line of the user that logged in.

Here is the simplified explanation of my program. The user will login ( the program will see if everything matches up[username/password] then return loginstatus =1 if the user login successfully) Once the user logs in the program will bring up a menu which will have 2 options.

1. it will let the user check it's current discount rate.
2. quit.