function template
<complex>

std::arg

complex (1)
template<class T> T arg (const complex<T>& x);
complex (1)
template<class T> T arg (const complex<T>& x);
arithmetic type (2)
double arg (ArithmeticType x);  // additional overloads
Phase angle of complex
Returns the phase angle (or angular component) of the complex number x, expressed in radians.

The phase angle of a complex number is the angle the theoretical vector to (real,imag) forms with the real axis (i.e., its arc tangent). It returns the same as
1
atan2(x.imag(),x.real());

Only available for instantiations of complex.
附加過載為任何 基本算術型別 提供:在這種情況下,函式假定該值為零 虛部
The return type is double, except if the argument is float or long double (in which case, the return type is of the same type as the argument).

引數

x
Complex value.

返回值

Phase angle of x.
Tcomplex 型別的分量型別(即其值型別)。

示例

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// arg complex example
#include <iostream>     // std::cout
#include <complex>      // std::complex, std::abs, std::arg

int main ()
{
  std::complex<double> mycomplex (3.0,4.0);

  std::cout << "The polar form of " << mycomplex;
  std::cout << " is " << std::abs(mycomplex) << "*e^i*" << std::arg(mycomplex) << "rad\n";

  return 0;
}

輸出

The polar form of (3,4) is 5*e^i*0.927295rad


另見