错误：数组new中的大小必须具有整数类型[-fpermissive]

Question

我正在使用动态内存分配来创建新对象，当我尝试编译时，以下错误不断出现。我将dimensions_创建为unsigned int，因此我不确定为什么会出现此错误。

EuclideanVector.h:69:40: error: size in array new must have integral type [-fpermissive]
                         magnitude_  =  new double [dimensions_];

以下是错误指向的代码：

// target constructor for delegating constructor
template <typename NUM1, typename NUM2> // any numeric types of user input for dimensions and magnitude will be static_cast to unsigned int and double respectively
EuclideanVector(const NUM1 dimensions, const NUM2 magnitude){

            // static cast to unsigned int for temp and assign dimensions_ to that
            unsigned int temp = static_cast<unsigned int>(dimensions);
            dimensions_ = new unsigned int (temp);

            // assign pointer "magnitude_" to dynamically-allocated memory of new unnamed array<double> object of size "dimensions_"
            magnitude_  =  new double [dimensions_];

            // fill the array<double> object "magnitude_" a number of "dimensions_" times, with the <double> value of "magnitude_" for each dimension
            std::fill_n(magnitude_, dimensions_, static_cast<double>(magnitude));

            updateNormal();
      }

Answer 1

dimensions_是从unsigned int返回的指针，而不是new unsigned int (temp); 您需要magnitude_ = new double [*dimensions_];

之类的内容

Answer 2

您不能将指针用作数组大小。

＆＃34;在运行时计算的大小数组的一般解决方案＆＃34;是使用std::vector。