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Why do we copy then move?
...rvalues, the above would not compile.
Won't a copy be expensive, especially given something like std::string?
If you pass an rvalue, that will be moved into str, and that will eventually be moved into data. No copying will be performed. If you pass an lvalue, on the other hand, that lvalue wil...
What is the Sign Off feature in Git for?
...nto the Linux kernel and a few other projects, but most projects don't actually use it.
It was introduced in the wake of the SCO lawsuit, (and other accusations of copyright infringement from SCO, most of which they never actually took to court), as a Developers Certificate of Origin. It is used to...
How should one use std::optional?
...std::string s, int& i);
Another way that this could be done is especially bad:
int* try_parse_int(std::string s); //return nullptr if fail
This requires dynamic memory allocation, worrying about ownership, etc. - always prefer one of the other two signatures above.
Another example:
clas...
Can C++ code be valid in both C++03 and C++11 but do different things?
... // #1
void f(...); // #2
template<int N> void g() {
f(0*N); // Calls #2; used to call #1
}
Rounded results after integer division and modulo
In C++03 the compiler was allowed to either round towards 0 or towards negative infinity. In C++11 it is mandatory to round towards 0
int i = (-1) ...
Multi-gradient shapes
...intDrawable();
p.setShape(new RectShape());
p.setShaderFactory(sf);
Basically, the int array allows you to select multiple color stops, and the following float array defines where those stops are positioned (from 0 to 1). You can then, as stated, just use this as a standard Drawable.
Edit: Here's...
社交应用组件 · App Inventor 2 中文网
...ns a list of the most recent messages mentioning the logged-in user.
Initially, the list is empty. To set it, the program must:
Call the Authorize method.
Wait for the IsAuthorized event.
Call the RequestDirectMessages method.
4, Wait for the DirectMessagesReceived event.
...
Canvas width and height in HTML5
...t would be much faster to just reset the css, no?(rather than loop through all objects)...
– EnglishAdam
Sep 11 '14 at 9:28
...
What is the correct way of using C++11's range-based for?
...x << ' ';
}
the output is something like:
[... copy constructor calls for vector<X> initialization ...]
Elements:
X copy ctor.
1 X copy ctor.
3 X copy ctor.
5 X copy ctor.
7 X copy ctor.
9
As it can be read from the output, copy constructor calls are made during range-based for l...
In Java, what is the best way to determine the size of an object?
...ect. Is there an easy way to find out the size of that object programmatically? Is there a reference that defines how large primitive types and object references are for a VM ?
...
How to select rows from a DataFrame based on column values?
...have multiple values you want to include, put them in a
list (or more generally, any iterable) and use isin:
print(df.loc[df['B'].isin(['one','three'])])
yields
A B C D
0 foo one 0 0
1 bar one 1 2
3 bar three 3 6
6 foo one 6 12
7 foo three 7 14
Note,...