[流程控制] 疑问goto语句逻辑判断

PROGRAM AAA

IMPLICIT NONE
LOGICAL Y,N,NN

100 WRITE(*,*) "Y/N?"
    READ(*,*) NN
IF (Y=NN) THEN
    GOTO 200
ELSE IF (N=NN) THEN
    GOTO 300   
ELSE
     GOTO 100
END IF
200 WRITE(*,*) "200"
300 WRITE(*,*) "300"

END

Program AAA
  Implicit None
  Character NN
  Do
    write(*,*) "Y/N?"
    read(*,*) NN
    If ( 'Y'==NN ) then
      write(*,*) "200"
    Else If ( 'N'==NN ) then
      write(*,*) "300"
    Else
      cycle
    End If
    exit
  End Do
End Program AAA