va_copy
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<metanoindex/>
<tbody>| definiert in Header <cstdarg>
|
void va_copy(va_list dest, va_list src); |
(seit C++11) | |
</tbody>
Die
va_copy Makro kopiert src um dest .Original:
The
va_copy macro copies src to dest.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
va_end sollte auf
dest bevor die Funktion zurückkehrt oder eine spätere Re-Initialisierung des dest aufgerufen werden (über Anrufe va_start oder va_copy) .Original:
va_end should be called on
dest before the function returns or any subsequent re-initialization of dest (via calls to va_start or va_copy).The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Inhaltsverzeichnis
Parameter
| dest | - | eine Instanz der va_list geben zu initialisieren
Original: an instance of the va_list type to initialize The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| src | - | die Quelle va_list, die verwendet werden, um
dest initialisiert werden Original: the source va_list that will be used to initialize dest The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
Expanded Wert
(None)
Original:
(none)
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Beispiel
#include <iostream>
#include <cstdarg>
#include <cmath>
double sample_stddev(int count, ...)
{
double sum = 0;
va_list args1;
va_start(args1, count);
va_list args2;
va_copy(args2, args1);
for (int i = 0; i < count; ++i) {
double num = va_arg(args1, double);
sum += num;
}
double mean = sum / count;
double sum_sq_diff = 0;
for (int i = 0; i < count; ++i) {
double num = va_arg(args2, double);
sum_sq_diff += (num-mean) * (num-mean);
}
return std::sqrt(sum_sq_diff / count);
}
int main()
{
std::cout << sample_stddev(4, 25.0, 27.3, 26.9, 25.7) << '\n';
}
Output:
0.920258
Siehe auch
ermöglicht den Zugriff auf variadische Funktionsargumente Original: enables access to variadic function arguments The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funktionieren Makro) | |
greift auf die nächsten variadische Funktionsargument Original: accesses the next variadic function argument The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funktionieren Makro) | |
endet Durchlaufen der variadische Funktionsargumente Original: ends traversal of the variadic function arguments The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funktionieren Makro) |