Double Linked List

1
Double Linked List

• OTA Takashi

2
Double Link in HTML 4.01

• http//www.w3.org/TR/html4/struct/links.htmlrev-l
  ink
• Consider two documents A and B.
• Document A ltLINK href"docB" rel"foo"gt
• Has exactly the same meaning as
• Document B ltLINK href"docA" rev"foo"gt
• You mean...
• docA ? docB

3
Difference from Single Linked List

• When you use single linked list...
• You can go from A to B
• But cannot go from B to A
• lta href...gt..lt/agt is a single link
• With Double Linked List
• You can go both
• From A to B, and...
• From B to A

4
And I'd like to ask you...

• How many people have you ever used directory
  stack?

5
What is stack?

• Last In, First Out (LIFO)
• Push
• A,B,C,....?D
• Pop
• A,B,C,....?D
• Opposite to queue

6
Directory stack

• Use as an alternative to cd
• pushd
• Push a directory to the stack
• popd
• Pop a directory from the stack
• dirs
• Show your directory stack
• Useful when you go back and forth 2 or more
  directories.
• See also man pushd or so.

7
Other C-shell list structures

• Whyle
• Why named whyle, not while?
• Because while is reserved word.
• Process
• process-gtp_next
• process-gtp_friends

8
Homework

• Choose your faviorite shell
• Find a source...
• Look up where directory stack manipulated...
• Paste its partial source and introduce its
  algorithms of double linked list in your words.
• sh, ash, ksh, bash, csh, tcsh, zsh, fdsh, ...
• Mail to takot_at_tom.sfc.keio.ac.jp
• saying Subject homework Apr27
• Until Mon May 10, 2004