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When to use extern in C++
I'm reading "Think in C++" and it just introduced the extern declaration. For example:
4 Answers
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PHP - iterate on string characters
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Step 1: convert the string to an array using the str_split function
$array = str_split($your_string);
Step 2: loop through the newly created array
foreach ($array as $char) {
echo $char;
}
You can check the PHP docs for more in...
Comparing two collections for equality irrespective of the order of items in them
... comparer. It is more complete than existing answers, since it takes nulls into account, implements IEqualityComparer and has some efficiency and edge case checks. plus, it's Microsoft :)
public class MultiSetComparer<T> : IEqualityComparer<IEnumerable<T>>
{
private readonly I...
How dangerous is it to compare floating point values?
...th scanf or strtod, do not exist as floating point values and get silently converted to the nearest approximation. This is what demon9733's answer was talking about.
The fact that many results get rounded due to not having enough precision to represent the actual result. An easy example where you ca...
Replacing column values in a pandas DataFrame
...e this:
w['female'] = w['female'].map({'female': 1, 'male': 0})
(Here I convert the values to numbers instead of strings containing numbers. You can convert them to "1" and "0", if you really want, but I'm not sure why you'd want that.)
The reason your code doesn't work is because using ['femal...
How to define “type disjunction” (union types)?
...declare a class with the types you wish to accept as below:
class StringOrInt[T]
object StringOrInt {
implicit object IntWitness extends StringOrInt[Int]
implicit object StringWitness extends StringOrInt[String]
}
Next, declare foo like this:
object Bar {
def foo[T: StringOrInt](x: T) = x ...
How to get screen dimensions as pixels in Android
... use getSize:
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int height = size.y;
If you're not in an Activity you can get the default Display via WINDOW_SERVICE:
WindowManager wm = (WindowManager) context.getSystemS...
How do I return multiple values from a function in C?
If I have a function that produces a result int and a result string , how do I return them both from a function?
8 Answe...
Default value to a parameter while passing by reference in C++
... way round this would be to use an actual instance as the default:
static int AVAL = 1;
void f( int & x = AVAL ) {
// stuff
}
int main() {
f(); // equivalent to f(AVAL);
}
but this is of very limited practical use.
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Is there a range class in C++11 for use with range based for loops?
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There has been much progress lately to get ranges into the standard (N4128). See github.com/ericniebler/range-v3 for a proposal and reference implementation.
– Ela782
Feb 21 '15 at 19:27
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