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Virtual/pure virtual explained
What exactly does it mean if a function is defined as virtual and is that the same as pure virtual?
12 Answers
...
What does “fragment” mean in ANTLR?
...is somewhat akin to an inline function: It makes the grammar more readable and easier to maintain.
A fragment will never be counted as a token, it only serves to simplify a grammar.
Consider:
NUMBER: DIGITS | OCTAL_DIGITS | HEX_DIGITS;
fragment DIGITS: '1'..'9' '0'..'9'*;
fragment OCTAL_DIGITS: '...
Unique combination of all elements from two (or more) vectors
...s better than the classic expand.grid function because (1) strings are not converted into factors and (2) the sorting is more intuitive:
library(tidyr)
a <- c("ABC", "DEF", "GHI")
b <- c("2012-05-01", "2012-05-02", "2012-05-03", "2012-05-04", "2012-05-05")
crossing(a, b)
# A tibble: 15 x 2...
Should we pass a shared_ptr by reference or by value?
...
This question has been discussed and answered by Scott, Andrei and Herb during Ask Us Anything session at C++ and Beyond 2011. Watch from 4:34 on shared_ptr performance and correctness.
Shortly, there is no reason to pass by value, unless the goal is to sha...
What is a proper naming convention for MySQL FKs?
... users(user_id);
I try to stick with the same field names in referencing and referenced tables, as in user_id in the above example. When this is not practical, I also append the referenced field name to the foreign key name.
This naming convention allows me to "guess" the symbolic name just by l...
Mercurial: Can I rename a branch?
...ms where you can force the users to clone this is a good idea -- or use hg convert instead.
– hochl
Apr 3 '12 at 8:34
5
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Use of #pragma in C
...ion, override some default, etc. that may or may not apply to all machines and operating systems.
See msdn for more info.
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git replacing LF with CRLF
...ut something, all text files automatically will have their LF line endings converted to CRLF endings. This allows development of a project across platforms that use different line-ending styles without commits being very noisy because each editor changes the line ending style as the line ending sty...
Comparing date part only without comparing time in JavaScript
...one when you create, you now need to be sure to keep timezone out when you convert back to a string representation. So you can safely use...
toISOString()
getUTCxxx()
getTime() //returns a number with no time or timezone.
.toLocaleDateString("fr",{timeZone:"UTC"}) // whatever locale you want, but A...
Best way to implement Enums with Core Data
... kPaymentFrequencyWeekly = 3
} PaymentFrequency;
Then, declare getters and setters for your property. It's a bad idea to override the existing ones, since the standard accessors expect an NSNumber object rather than a scalar type, and you'll run into trouble if anything in the bindings or KVO sy...