3 ms·

I just took a look at the rangeCheck: https://majadhondt.wordpress.com/2012/05/16/googles-9-lines/ https://majadhondt.wordpress.com/2012/05/16/googles-9-lines/

I just took a look at the rangeCheck: https://majadhondt.wordpress.com/2012/05/16/googles-9-lines/ https://majadhondt.wordpress.com/2012/05/16/googles-9-lines/ Is this example correct? Can someone explain to me how this: if (toIndex > arrayLen) is correct? If the array length is say 5, and toIndex is 5, that should still throw an index out of bounds exception, right? But it would be acceptable here.

mikevm 6y ago
toIndex is defined to be the index after the last element of the range (a half-closed interval).
Jabbles 6y ago
The example is correct. toIndex is exclusive. Here is Dijkstra's opinion on why: https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/EWD831.html https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/E...
tomsmeding 6y ago
Aside from the questionable inequalities, there's a missing closing parenthesis after the arguments on the first line, too. EDIT: as has been pointed out, the inequalities are correct. The original code can e.g. be found here, including doc comments showing the intended meaning of the arguments: http://www.groklaw.net/pdf3/OraGoogletrialexhibits/2012-04-20/0045.001.pdf http://www.groklaw.net/pdf3/OraGoogletrialexhibits/2012-04-2... (all the way at the end)
- distribot 6y ago
  Thanks this makes sense. So the toIndex is literally defined as "the index after the last element in the range".
jameshart 6y ago
The upper bound of the range is intended to be exclusive, while the lower bound is inclusive - basically, the same s array indexing convention. It allows the case where fromIndex == toIndex to represent the empty range (note that this check does permit fromIndex to equal toIndex, but never to exceed it), and the number of entries in a given range is always defined by toIndex - fromIndex.
asgeir 6y ago
This is correct for a half-closed interval https://mathworld.wolfram.com/Half-ClosedInterval.html https://mathworld.wolfram.com/Half-ClosedInterval.html

mikevm 6y ago

toIndex is defined to be the index after the last element of the range (a half-closed interval).

Jabbles 6y ago

The example is correct. toIndex is exclusive. Here is Dijkstra's opinion on why: https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/EWD831.html https://www.cs.utexas.edu/users/EWD/transcriptions/EWD08xx/E...

tomsmeding 6y ago

Aside from the questionable inequalities, there's a missing closing parenthesis after the arguments on the first line, too. EDIT: as has been pointed out, the inequalities are correct. The original code can e.g. be found here, including doc comments showing the intended meaning of the arguments: http://www.groklaw.net/pdf3/OraGoogletrialexhibits/2012-04-20/0045.001.pdf http://www.groklaw.net/pdf3/OraGoogletrialexhibits/2012-04-2... (all the way at the end)

distribot 6y ago
Thanks this makes sense. So the toIndex is literally defined as "the index after the last element in the range".

jameshart 6y ago

The upper bound of the range is intended to be exclusive, while the lower bound is inclusive - basically, the same s array indexing convention. It allows the case where fromIndex == toIndex to represent the empty range (note that this check does permit fromIndex to equal toIndex, but never to exceed it), and the number of entries in a given range is always defined by toIndex - fromIndex.

asgeir 6y ago

This is correct for a half-closed interval https://mathworld.wolfram.com/Half-ClosedInterval.html https://mathworld.wolfram.com/Half-ClosedInterval.html