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Declaring variables inside loops, good practice or bad practice?
...; counter <= 10; counter++) {
// compiler can pull this out
const char testing[] = "testing";
cout << testing;
}
or you can pull the constant out:
const std::string testing = "testing";
for (int counter = 0; counter <= 10; counter++) {
cout << testing;
}
Do most...
I want to get the type of a variable at runtime
... case _: B => "A is a B"
case _ => "A is not a B"
}
f(x, y) // A (Char) is not a B (Int)
f(x, z) // A (Char) is a B (Any)
Here I'm using the context bounds syntax, B : ClassTag, which works just like the implicit parameter in the previous ClassTag example, but uses an anonymous variable.
...
Split List into Sublists with LINQ
...";
int count = 0;
// Group by three.
foreach (IEnumerable<char> g in s.Chunk(3))
{
// Print out the group.
Console.Write("Group: {0} - ", ++count);
// Print the items.
foreach (char c in g)
{
// Print the item.
...
The static keyword and its various uses in C++
... do different things. For instance, you could put a static void log(const char*) {} in each cpp file, and they could each all log in a different way.
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Are the days of passing const std::string & as a parameter over?
...ring has various components including a pointer into the heap and a member char[] for short string optimization. So it seems to me that passing by reference is still a good idea. Can anyone explain why Herb might have said this?
If stack size is a concern (and assuming this is not inlined/optimize...
application/x-www-form-urlencoded or multipart/form-data?
...ueTwo
According to the specification:
[Reserved and] non-alphanumeric characters are replaced by `%HH', a percent sign and two hexadecimal digits representing the ASCII code of the character
That means that for each non-alphanumeric byte that exists in one of our values, it's going to take th...
How to write a large buffer into a binary file in C++, fast?
...stream("file.binary", std::ios::out | std::ios::binary);
myfile.write((char*)&data[0], bytes);
myfile.close();
auto endTime = std::chrono::high_resolution_clock::now();
return std::chrono::duration_cast<std::chrono::milliseconds>(endTime - startTime).count();
}
long long ...
What is the difference between quiet NaN and signaling NaN?
...trtod and 7.22.1.3 "The strtod, strtof, and strtold functions" says:
A character sequence NAN or NAN(n-char-sequence opt ) is interpreted as a quiet
NaN, if supported in the return type, else like a subject sequence part that does not have
the expected form; the meaning of the n-char sequenc...
App Inventor 2 串口通信教程 - USB串口与蓝牙串口 · App Inventor 2 中文网
...块接收数据（来自手机 App）
if (Serial.available() > 0) {
char command = Serial.read();
switch (command) {
case '1':
// 打开 LED
digitalWrite(13, HIGH);
Serial.println("LED ON");
break;
case '0':
// 关闭 LED
digital...
Why should C++ programmers minimize use of 'new'?
...ts. std::string is a perfect example. This snippet:
int main ( int argc, char* argv[] )
{
std::string program(argv[0]);
}
actually allocates a variable amount of memory. The std::string object allocates memory using the heap and releases it in its destructor. In this case, you did not need ...