new empty 1 size 0 head0 push_front 13 empty 0 size 1 head retrieve 13 next retrieve 13 exit push_front 14 empty 0 size 2 head retrieve 14 next retrieve 13 next retrieve 14 exit push_front 15 empty 0 size 3 head retrieve 15 next retrieve 14 next retrieve 13 next retrieve 15 exit push_front 16 empty 0 size 4 head retrieve 16 next retrieve 15 next retrieve 14 next retrieve 13 next retrieve 16 exit push_back 12 empty 0 size 5 head retrieve 16 next retrieve 15 next retrieve 14 next retrieve 13 next retrieve 12 next retrieve 16 exit pop_front 16 empty 0 size 4 head retrieve 15 next retrieve 14 next retrieve 13 next retrieve 12 next retrieve 15 exit pop_back 12 empty 0 size 3 head retrieve 15 next retrieve 14 next retrieve 13 next retrieve 15 exit pop_front 15 pop_back 13 pop_front 14 empty 1 size 0 head0 delete new member 1 0 size 0 front! back! head0 empty 1 push_front 1 member 1 1 size 1 front 1 back 1 empty 0 head retrieve 1 previous retrieve 1 next retrieve 1 exit pop_front 1 size 0 front! back! head0 empty 1 push_front 1 pop_back 1 size 0 front! back! head0 empty 1 push_front 3 push_back 4 push_front 2 push_back 5 push_front 1 size 5 front 1 back 5 head retrieve 1 next retrieve 2 next retrieve 3 next retrieve 4 next retrieve 5 next retrieve 1 previous retrieve 5 previous retrieve 4 previous retrieve 3 previous retrieve 2 previous retrieve 1 exit member 1 1 member 3 1 member 5 1 pop_front 1 size 4 front 2 back 5 head retrieve 2 next retrieve 3 next retrieve 4 next retrieve 5 next retrieve 2 previous retrieve 5 previous retrieve 4 previous retrieve 3 previous retrieve 2 exit pop_back 5 size 3 front 2 back 4 head retrieve 2 next retrieve 3 next retrieve 4 next retrieve 2 previous retrieve 4 previous retrieve 3 previous retrieve 2 exit push_front 1 push_back 5 remove 1 1 size 4 front 2 back 5 head retrieve 2 next retrieve 3 next retrieve 4 next retrieve 5 next retrieve 2 previous retrieve 5 previous retrieve 4 previous retrieve 3 previous retrieve 2 exit remove 5 1 size 3 front 2 back 4 head retrieve 2 next retrieve 3 next retrieve 4 next retrieve 2 previous retrieve 4 previous retrieve 3 previous retrieve 2 exit remove 5 0 head retrieve 2 next retrieve 3 next retrieve 4 next retrieve 2 previous retrieve 4 previous retrieve 3 previous retrieve 2 exit remove 3 1 size 2 head retrieve 2 next retrieve 4 next retrieve 2 previous retrieve 4 previous retrieve 2 exit remove 2 1 size 1 head retrieve 4 next retrieve 4 previous retrieve 4 exit remove 2 0 remove 4 1 size 0 empty 1 front! back! pop_front! pop_back! push_front 8 push_front 9 push_front 8 remove 8 1 front 9 back 8 size 2 remove 8 1 front 9 back 9 size 1 remove 9 1 size 0 front! back! delete summary exit