qbasic-What is wrong with my code?I'm not getting what i want - qbasic

Question

I tried to make a simple login program using qbasic. I used 3 sub modules and 1 main module. Here is the code:
DECLARE SUB login ()
DECLARE SUB menu ()
DECLARE SUB REGISTER ()
CLS
CALL menu
END
SUB login
OPEN "USERPASS.TXT" FOR INPUT AS #2
CLS
97
LOCATE 2, 30: PRINT "LOGIN"
LOCATE 4, 10: INPUT "PLEASE ENTER CORRECT USERNAME OR PRESS B IF YOU WANT TO GO BACK"; USER$
IF UCASE$(USER$) = "B" THEN
CLOSE #2
CALL menu
ELSE
DO WHILE NOT EOF(2)
INPUT #2, U$, p$
IF U$ = USER$ THEN
TEMPUSER$ = U$
PASSWORDS$ = p$
EXIT DO
END IF
LOOP
END IF
IF USER$ = TEMPUSER$ THEN
98
PRINT PASSWORDS$
LOCATE 5, 30: INPUT "ENTER PASSWORD OR PRESS B if you want to go back"; password$
IF UCASE$(password$) = "B" THEN
GOTO 97
ELSE
IF password$ = PASSWORDS$ THEN
PRINT "HURRAY YOU LOGGED IN"
ELSE
GOTO 98
END IF
END IF
ELSE
GOTO 97
END IF
CLOSE #2
END SUB
SUB menu
CLS
23
LOCATE 2, 30: PRINT "MAIN MENU"
LOCATE 4, 30: PRINT "1.LOGIN"
LOCATE 5, 30: PRINT "2.REGISTER"
LOCATE 6, 30: INPUT "PLEASE! Enter 1 or 2"; a
IF a = 1 THEN
CALL login
ELSE
IF a = 2 THEN
CALL REGISTER
ELSE
CLS
GOTO 23
END IF
END IF
END SUB
SUB REGISTER
CLS
OPEN "userpass.txt" FOR APPEND AS #1
LOCATE 2, 30: PRINT "REGISTER MENU"
LOCATE 4, 30: INPUT "ENTER NEW USERNAME"; NEWU$
CLS
LOCATE 4, 30: INPUT "ENTER NEW PASSWORD"; PASSU$
WRITE #1, NEWU$, PASSU$
END SUB
Everything is as my desire but in sub module login something is wrong I guess. The login massage does not come even if I enter correct password and username. But if I enter username which does not exist, it shows the login message. Please help. Thanks in advance.

Answer 1

You're missing an END IF to match ELSEIF UCASE$(USER$) <> "B" THEN (by the way: if UCASE$(USER$) = "B" is false, then UCASE$(USER$) <> "B" is true, so you could simply say ELSE there).
You might try indenting in a bit more conventional manner:
every IF, ELSEIF, ELSE, and END IF that matches is in the same column, and
everything inside those statements is indented a few more spaces.
The same indentation rules can be applied to SELECT CASE, WHILE-WEND, DO-LOOP, and FOR-NEXT.
Anyway, you might see the missing END IF if you did that:
SUB login
OPEN "USERPASS.TXT" FOR INPUT AS #2
CLS
97
LOCATE 2, 30: PRINT "LOGIN"
LOCATE 4, 10: INPUT "PLEASE ENTER CORRECT USERNAME OR PRESS B IF YOU WANT TO GO BACK"; USER$
IF UCASE$(USER$) = "B" THEN
CLOSE #2
CALL menu
ELSEIF UCASE$(USER$) <> "B" THEN
WHILE NOT EOF(2)
INPUT #2, U$, p$
IF U$ = USER$ THEN
TEMPUSER$ = U$
PASSWORDS$ = p$
END IF
WEND
IF USER$ = TEMPUSER$ THEN
98
PRINT PASSWORDS$
LOCATE 5, 30: INPUT "ENTER PASSWORD OR PRESS B if you want to go back"; password$
IF UCASE$(password$) = "B" THEN GOTO 97
ELSEIF UCASE$(password$) <> "B" THEN
IF password$ = PASSWORDS$ THEN
PRINT "HURRAY YOU LOGGED IN"
ELSE
GOTO 98
END IF
END IF
ELSE
GOTO 97
END IF
CLOSE #2
END SUB