Driver code
if __name__ == ' _ _ main _ _ ' : NEW_LINE INDENT mat = [ 1 , 2 , 3 , 4 ] , [ 5 , 6 , 7 , 8 ] , [ 9 , 10 , 11 , 12 ] , [ 13 , 14 , 15 , 16 ] ; NEW_LINE n = 4 ; NEW_LINE imageSwap ( mat , n ) ; NEW_LINE printMatrix ( mat , n ) ; NEW_LINE DEDENT