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Difference between `set`, `setq`, and `setf` in Common Lisp?
What is the difference between "set", "setq", and "setf" in Common Lisp?
6 Answers
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Quick-and-dirty way to ensure only one instance of a shell script is running at a time
What's a quick-and-dirty way to make sure that only one instance of a shell script is running at a given time?
40 Answers
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Counting inversions in an array
... find all inversion pairs such that A[i] > A[j] . I'm using merge sort and copying array A to array B and then comparing the two arrays, but I'm having a difficult time seeing how I can use this to find the number of inversions. Any hints or help would be greatly appreciated.
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How do iOS Push Notifications work?
...ered to receive those notifications. Each device establishes an accredited and encrypted IP connection with the service and receives notifications over this persistent connection. Providers connect with APNs through a persistent and secure channel while monitoring incoming data intended for their cl...
How can I exclude all “permission denied” messages from “find”?
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Note:
* This answer probably goes deeper than the use case warrants, and find 2>/dev/null may be good enough in many situations. It may still be of interest for a cross-platform perspective and for its discussion of some advanced shell techniques in the interest of finding a solution that i...
java.lang.UnsupportedClassVersionError: Bad version number in .class file?
... suggestions on the web indicate that the code was compiled in one version and executed in another version (new on old). However, I only have one version of JRE on my system. If I run the commands:
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How to split a string and assign it to variables
In Python it is possible to split a string and assign it to variables:
9 Answers
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Is there a difference between YES/NO,TRUE/FALSE and true/false in objective-c?
Simple question really; is there a difference between these values (and is there a difference between BOOL and bool)? A co-worker mentioned that they evaluate to different things in Objective-C, but when I looked at the typedefs in their respective .h files, YES/TRUE/true were all defined as 1 an...
~x + ~y == ~(x + y) is always false?
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Assume for the sake of contradiction that there exists some x and some y (mod 2n) such that
~(x+y) == ~x + ~y
By two's complement*, we know that,
-x == ~x + 1
<==> -1 == ~x + x
Noting this result, we have,
~(x+y) == ~x + ~y
<==> ~(x+y) + (x+y) == ~x + ~y...
What is the difference between exit(0) and exit(1) in C?
Can anyone tell me? What is the difference between exit(0) and exit(1) in C language?
11 Answers
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