下面的代码无法使用-std = c 0x开关使用g版本4.5.0进行编译.我收到以下错误消息：
error: no match for 'operator+' in 'std::pow [with _Tp = float,_Up = int,typename __gnu_cxx::__promote_2<_Tp,_Up>::__type = double](((const std::complex<float>&)((const std::complex<float>*)(& x))),((const int&)((const int*)(&2)))) + y'
我认为这与here提到的可分配要求有关.我应该为复杂定义我自己的复制赋值运算符吗？如果是这样,怎么样？
#include <complex>
using namespace std;
int main(int argc,char *argv[]) {
complex<float> x,y;
x = pow(x,2); // ok
x = x + y; // ok
x = pow(x,2) + y; // error
return 0;
}
解决方法
[cmplx.over] / p3指定涉及复杂时的pow的额外重载：
Function template pow shall have additional overloads sufficient to
ensure,for a call with at least one argument of typecomplex<T>:
If either argument has type
complex<long double>or typelong double,then both arguments are effectively cast tocomplex<long.
double>Otherwise,if either argument has type
complex<double>,double,or an integer type,then both arguments are effectively cast to
complex<double>.Otherwise,if either argument has type
complex<float>orfloat,then both arguments are effectively cast tocomplex<float>.
2被提升为double,而pow(complex< float>,double)返回复数< double>.
