What does copying an object mean? What are the copy constructor and the copy assignment operator? When do I need to declare them myself? How can I prevent my objects from being copied?
What is this idiom and when should it be used? Which problems does it solve? Does the idiom change when C++11 is used? Although it's been mentioned in many places, we didn't have any singular "what i...
Until today, I thought that for example: i += j; is just a shortcut for: i = i + j; But what if we try this: int i = 5; long j = 8; Then i = i + j; will not compile but i += j; will compile f...
What are differences in the assignment operators '=' and '<-' in R? I know that operators are slightly different as this example shows x <- y <- 5 x = y = 5 x = y <- 5 x <- y = 5 # Err...
The documentation for PL/pgSQL says, that declaration and assignment to variables is done with :=. But a simple, shorter and more modern (see footnote) = seems to work as expected: CREATE OR REP...
What is the difference between the following Python expressions: # First: x,y = y,x+y # Second: x = y y = x+y First gives different results than Second. e.g., First: >>> x = 1 >&g...
In C++, the concept of returning reference from the copy assignment operator is unclear to me. Why can't the copy assignment operator return a copy of the new object? In addition, if I have class A, a...
What is the motivation for Scala assignment evaluating to Unit rather than the value assigned? A common pattern in I/O programming is to do things like this: while ((bytesRead = in.read(buffer)) != ...
I have a long set of comparisons to do in Java, and I'd like to know if one or more of them come out as true. The string of comparisons was long and difficult to read, so I broke it up for readability...
Why doesn't Java have compound assignment versions of the conditional-and and conditional-or operators? (&&=, ||=)
So for binary operators on booleans, Java has &, |, ^, && and ||. Let's summarize what they do briefly here: JLS 15.22.2 Boolean Logical Operators &, ^, and | JLS 15.23 Conditional-...