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Why does C++ require a user-provided default constructor to default-construct a const object?
The C++ standard (section 8.5) says:
5 Answers
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Format Instant to String
...-zone is required. Without a time-zone, the formatter does not know how to convert the instant to human date-time fields, and therefore throws an exception.
The time-zone can be added directly to the formatter using withZone().
DateTimeFormatter formatter =
DateTimeFormatter.ofLocalizedDateTim...
Access an arbitrary element in a dictionary in Python
...ction() results do not support indexing, this is why first of all we must convert it into a list and then we can use the index [0]
– Noki
May 24 '19 at 9:41
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Foreign Key to multiple tables
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You have a few options, all varying in "correctness" and ease of use. As always, the right design depends on your needs.
You could simply create two columns in Ticket, OwnedByUserId and OwnedByGroupId, and have nullable Foreign Keys to each table.
You could create M:M referen...
Is there a common Java utility to break a list into batches?
...s [[a, b, c], [d, e]] -- an outer list containing two inner lists of three and two elements, all in the original order.
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Inner class within Interface
... "static inner class": this simply makes no sense, there's nothing "inner" and no "outter" class when a nested class is static, so it cannot be "static inner").
Anyway, the following compiles fine:
public interface A {
class B {
}
}
I've seen it used to put some kind of "contract checker...
Why Choose Struct Over Class?
...n many circumstances.
Structs are preferable if they are relatively small and copiable because copying is way safer than having multiple references to the same instance as happens with classes. This is especially important when passing around a variable to many classes and/or in a multithreaded env...
Make copy of an array
...Let's say a = [1,2,3,4,5] . I need to make an exact duplicate copy of a and call it b . If a were to change to [6,7,8,9,10] , b should still be [1,2,3,4,5] . What is the best way to do this? I tried a for loop like:
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Command line progress bar in Java
I have a Java program running in command line mode.
I would like to display a progress bar, showing the percentage of job done.
The same kind of progress bar you would see using wget under unix.
Is this possible?
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Mapping many-to-many association table with extra column(s)
My database contains 3 tables:
User and Service entities have many-to-many relationship and are joined with the SERVICE_USER table as follows:
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