FORTRAN 90+: WHERE EXAMPLE

PROGRAM whereq
     IMPLICIT NONE
     REAL, DIMENSION(1:3,1:3) :: a,b,c
     LOGICAL, DIMENSION(1:3,1:3) :: d
     INTEGER :: i,j,num=1
          a(1,1:3)=0
          a(2:3,1:3)=2
          b(1,:)=(/1,2,3/)
          b(2,:)=(/4,5,6/)
          b(3,:)=(/7,8,9/)
     WHERE (a .EQ. 0)
          b=9
     END WHERE
     WHERE (a .NE. 0)
          c= b/a
     END WHERE
     d=a .NE. 0
     WRITE(*,"(3(3(3(2X,F4.2),/)/))") TRANSPOSE(a), & TRANSPOSE(b),&
     &TRANSPOSE(c) !Reason for TRANSPOSE discussed on formatting page
     WRITE(*,"(3(3(2X,L1)/)))") TRANSPOSE(d)
END PROGRAM whereq