Information Technology Reference
In-Depth Information
Colons and Semicolons
Colons are used to join related statements.
These small additional structures allow a large saving: the worst case is
reduced from
O
(
n
)
to
O
(
log
n
)
.
Colons are also used to introduce lists.
There are three phases: accumulation of distinct symbols, construction
of the tree, and the compression itself.
The elements in a list can be separated by semicolons, allowing commas or other
marks within each element.
There are three phases: accumulation of distinct symbols in a hash table;
construction of the tree, using a temporary array to hold the symbols for
sorting; and the compression itself.
A semicolon can also be used to divide a long sentence, or to set off part of a
sentence for emphasis.
In theory the algorithm would be more efficient with an array; but in
practice a tree is preferable.
Colons and semicolons are valuable but should not be overused.
Apostrophes
Many people seem to have trouble with apostrophes. Even professional writers get
them wrong now and again. But the rules are quite simple.
Singular possessives such as “the student's algorithm”, “Brandt's book”, and “Su
and Ling's method” require an apostrophe and an “s”. (Some people would write
“Su's and Ling's method”, which is fine too.) For some names ending in “-s”, such
as in “Williams's book”, you can optionally omit the “s” after the apostrophe. If
you are unsure, then the “s” should be given.
Plural possessives such as “students' passwords” require an apostrophe but no “s”.
Pronoun possessives such as “its” (as in “its speed”) and “hers” do not require an
apostrophe.
Contractions such as “it's” (as in “it is blue”) and “can't” require an apostrophe;
but note that contractions should be avoided in technical writing.
1
Other than in the cases above, apostrophes are not required. The uses “in the 1980's”,
“each of the CPU's”, “the computers's power supplies”, and “Goss' approach” are
all incorrect.
1
This topic is a text, not a technical contribution, and I've used contractions without shame.
