algorithm - Print a two dimensional array in an outward spiral -

i asked question in interview:

given (n x m)array, say:

1 2 3 4 5 6 7 8 9 

print elements if traversed spirally centre. in above case, answer

5 4 7 8 9 6 3 2 1 

being familiar printing array in inward spiral, suggested stacking elements , popping them later, told otherwise.

note : n not equal m

given nxn matrix (being n odd number), , starting @ center position [n/2, n/2], general path generate spiral is:

move  left      1      position move  down      1      position move right 1 2 positions move    1 2 positions move  left 1 3 positions move  down 1 3 positions move right 1 4 positions move    1 4 positions ... 

there pattern can follow.

edit after edition of op's question

if matrix nxm n != m or n or m even, first have clarify in question behavior expect when reach 1 of edges of matrix: stop? go on ignoring positions outside matrix?