complex<float>

描述可儲存皆為 float 類型之物件的有序對，第一個代表複數的實部，而第二個代表虛部。

語法

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

constexpr complex(
    const complex<float>& complexNum);

constexpr complex(
    const complex<double>& complexNum);

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

參數

_RealVal
要建構之複數實際部分的 型 float 別值。

_ImagVal
用於建構中複數虛部的 float 類型值。

complexNum
型別或long double型double別的複數，其實數和虛數部分用來初始化所建構之型float別的複數。

傳回值

float 類型的複數。

備註

類別樣板複雜至類型複雜類別的 float 明確特製化，只與類別範本在所定義的建構函式中不同。 從轉換成 float 是隱含的，但從 轉換成的較不安全floatlong double，必須是 explicit。double 使用 explicit 指派語法排除初始與型別轉換。

如需類別範本 complex的詳細資訊，請參閱 複雜類別。 如需類別範本 complex的成員清單，請參閱 。

範例

// complex_comp_flt.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 <float> c1 ( 4.0 , 5.0 );
   cout << "Specifying initial real & imaginary parts,\n"
        << " as type float gives c1 = " << c1 << endl;

   // The second constructor initializes values of the real &
   // imaginary parts using those of complex number of type double
   complex <double> c2double ( 1.0 , 3.0 );
   complex <float> c2float ( c2double );
   cout << "Implicit conversion from type double to type float,"
        << endl << "gives c2float = " << c2float << 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 ( 3.0 , 4.0 );
   complex <float> c3float ( c3longdouble );
   cout << "Explicit conversion from type long double to type float,"
        << endl << "gives c3float = " << c3float << endl;

   // The modulus and argument of a complex number can be recovered
   double absc3 = abs ( c3float);
   double argc3 = arg ( c3float);
   cout << "The modulus of c3 is recovered from c3 using: abs ( c3 ) = "
        << absc3 << endl;
   cout << "Argument of c3 is recovered from c3 using:"
        << endl << "arg ( c3 ) = "
        << argc3 << " radians, which is " << argc3 * 180 / pi
        << " degrees." << endl;
}
/* Output:
Specifying initial real & imaginary parts,
as type float gives c1 = (4,5)
Implicit conversion from type double to type float,
gives c2float = (1,3)
Explicit conversion from type long double to type float,
gives c3float = (3,4)
The modulus of c3 is recovered from c3 using: abs ( c3 ) = 5
Argument of c3 is recovered from c3 using:
arg ( c3 ) = 0.927295 radians, which is 53.1301 degrees.
*/

需求

標頭： <複雜>

命名空間：std

另請參閱

complex 類別
C++ 標準程式庫中的執行緒安全