Assembly Language

I am trying to store user's input as varD after displayed msg2. However, it automatically set al to "What is the value of D?", which is msg2. It does not give user any chance to enter anything. I have no idea how to deal with it, please help me solve this problem. Thanks for your time.

INCLUDE Irvine32.inc

.data varD BYTE ? msg2 BYTE "What is the value of D?",0

.code main PROC

; initialized varD mov edx,OFFSET msg2 CALL WriteString CALL ReadString ; returned to eax mov varD, AL ; store value to C ; display msg2 and al CALL WriteString CALL Crlf CALL WriteString

exit

main ENDP

END main