complex<double>

發行項
06/09/2015

描述儲存已排序的物件兩種 double*，* 第一個代表複數的實數部分和第二個代表虛數物件。

template<>
   class complex<double> {
public:
   complex(
      double _RealVal = 0, 
      double _ImagVal = 0
   );

   complex(
      const complex<double>& _ComplexNum
   );
   explicit complex(
      const complex<long double>& _ComplexNum
   );
   // rest same as template class complex
};

參數

_RealVal
型別 double 的值所建構的複數的實數部分的。
_ImagVal
型別 double 的值所建構的複數的虛數部分。
_ComplexNum
型別 float 複數實數及虛數用來初始化型別建構的 double 複數的或型別 long double 。

傳回值

型別 double複數。

備註

樣板類別複雜的明確特製化對型別 double 複雜類別的與它所定義的範本只有類別有建構函式。從 float 轉換為 double 允許是隱含的，不過，到 double 要求從 long double 轉換為 explicit。使用指派語法，使用 explicit 排除與型別轉換的初始。

如需範本類別 complex，請參閱 complex 類別。如需範本類別 complex成員的清單，請參閱複雜的成員。

範例

// complex_comp_dbl.cpp
// compile with: /EHsc
#include <complex>
#include <iostream>

int main( )
{
   using namespace std;
   double pi = 3.14159265359;

   // The first constructor specifies real & imaginary parts
   complex <double> c1 ( 4.0 , 5.0 );
   cout << "Specifying initial real & imaginary parts,\n"
        << " as type double gives c1 = " << c1 << endl;

   // The second constructor initializes values of the real &
   // imaginary parts using those of complex number of type float
   complex <float> c2float ( 4.0 , 5.0 );
   complex <double> c2double ( c2float );
   cout << "Implicit conversion from type float to type double,"
        << "\n gives c2double = " << c2double << endl;

   // The third constructor initializes values of the real &
   // imaginary parts using those of a complex number
   // of type long double
   complex <long double> c3longdouble ( 4.0 , 5.0 );
   complex <double> c3double ( c3longdouble );
   cout << "Explicit conversion from type float to type double,"
        << "\n gives c3longdouble = " << c3longdouble << endl;

   // The modulus and argument of a complex number can be recovered
   double absc3 = abs ( c3longdouble );
   double argc3 = arg ( c3longdouble );
   cout << "The modulus of c3 is recovered from c3 using: abs ( c3 ) = "
        << absc3 << endl;
   cout << "Argument of c3 is recovered from c3 using:\n arg ( c3 ) = "
        << argc3 << " radians, which is " << argc3 * 180 / pi
        << " degrees." << endl;
}