PROGRAM Math_Majik IMPLICIT NONE INTEGER num, tnum outa: DO PRINT*, "Type in your number (0 terminates)" READ*, num IF (num .LE. 0) EXIT inna: DO tnum = num/2 IF (2*tnum .EQ. num) THEN ! num even num = tnum ELSE ! Odd num = 3*num+1 END IF PRINT*, num IF (num == 1) THEN PRINT*, "Sequence finishes nicely" EXIT ELSE IF (num == 13) THEN PRINT*, "Yoiks, Extreme bad luck encountered - Exit" EXIT outa END IF END DO inna END DO outa END PROGRAM Math_Majik