Understanding Computation

Errata for Understanding Computation

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The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".

The following errata were submitted by our customers and approved as valid errors by the author or editor.

Color key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update

Version Location Description Submitted By Date submitted Date corrected
PDF, ePub
Page 69
paragraph below the info box about the #tap method

The name of the method must be #read_string, not #read_string? because it does not have a boolean return value. In the code sample a couple of lines above it is named correctly.

Note from the Author or Editor:
In the paragraph before the "Nondeterministic Finite Automata" heading, the question mark at the end of #read_string? should be deleted.

sebroeder  Jun 03, 2013 
Page 70
4th paragraph

The accept states in the figure given are wrong. State 3 and state 5 are shown as accept states while they are not accept states. State 4 is not show as accept state while it actually is an accept state (the only one).

Note from the Author or Editor:
The figure should look like Namely:

* The arrow from 3 to 4 should be labelled "a", not "b".
* The arrow from 3 to 5 should be labelled "b", not "a".
* The circle around 3 should have a single-line border, not a double-line border.

Michel Rijnders  May 21, 2013  May 31, 2013
Page 77

State 4 is an accept state, so the circle around the 4 should have a double-line border, not a single-line border. (See

Tom Stuart
May 23, 2013  May 31, 2013
Page 259
Middle paragraph

Accidentally repeated word: "to to" should be "to" in "Of course, this scheme of encoding a program as a large number is what makes it possible ***to to*** store it on disk,..."

Jacob Quant  Aug 08, 2015