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Returning unique_ptr from functions
...the object were designated by an rvalue.
Just wanted to add one more point that returning by value should be the default choice here because a named value in the return statement in the worst case, i.e. without elisions in C++11, C++14 and C++17 is treated as an rvalue. So for example the follo...
How to save a PNG image server-side, from a base64 data string
I'm using Nihilogic's "Canvas2Image" JavaScript tool to convert canvas drawings to PNG images.
What I need now is to turn those base64 strings that this tool generates, into actual PNG files on the server, using PHP.
...
What is a “context bound” in Scala?
... to Scala 2.7, tabulate could be
written as follows:
def tabulate[T](len: Int, f: Int => T) = {
val xs = new Array[T](len)
for (i <- 0 until len) xs(i) = f(i)
xs
}
In Scala 2.8 this is no longer possible, because runtime information is necessary to create the right representatio...
Will using goto leak variables?
...abels).
1. Label scope
You can't jump across functions:
void f() {
int x = 0;
goto lol;
}
int main() {
f();
lol:
return 0;
}
// error: label 'lol' used but not defined
[n3290: 6.1/1]: [..] The scope of a label is the function in which
it appears. [..]
2. Object initiali...
Quicksort vs heapsort
...hough there remains
the chance of worst case performance
except in the introsort variant, which
switches to heapsort when a bad case
is detected. If it is known in advance
that heapsort is going to be
necessary, using it directly will be
faster than waiting for introsort to
switch to...
BSS段、数据段、代码段、堆与栈 剖析 - C/C++ - 清泛网 - 专注C/C++及内核技术
...区。
【例一】
用cl 编译两个小程序如下：
程序1:
int ar[30000];
void main()
{
......
}
程序2:
int ar[300000] = {1, 2, 3, 4, 5, 6 };
void main()
{
......
}
发现程序2 编译之后所得的.exe 文件比程序1 的要大得多。当下甚为不解，于...
C++ Double Address Operator? (&&)
...
&& is new in C++11. int&& a means "a" is an r-value reference. && is normally only used to declare a parameter of a function. And it only takes a r-value expression. If you don't know what an r-value is, the simple explanation is...
Choose newline character in Notepad++
...
"Edit -> EOL Conversion". You can convert to Windows/Linux/Mac EOL there. The current format is displayed in the status bar.
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When should the xlsm or xlsb formats be used?
...memory,
the file format has no effect on application/calculation speed
Converters – both formats will have identical converter support
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Android: upgrading DB version and adding new table
...es, you want to be sure to check oldVersion:
onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
switch(oldVersion) {
case 1:
db.execSQL(DATABASE_CREATE_color);
// we want both updates, so no break statement here...
case 2:
db.execSQL(DATABASE_CREATE_someoth...