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.
附加重载为任何 基本算术类型 提供：在这种情况下，函数假定该值为零 虚部。
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).

参数

x
Complex value.

返回值

Phase angle of x.
T 是 complex 类型的分量类型（即其值类型）。

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;
}

输出

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


另见

abs
复数的绝对值 (函数模板)
polar
从极坐标分量创建复数 (函数模板)