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std::arg(std::complex)_C++中文网

定义于头文件 <complex>

template< class T >
T arg( const complex<T>& z );

 (1)

long double arg( long double z );

 (2) (C++11 起)

template< class DoubleOrInteger >
double arg( DoubleOrInteger z );

 (3) (C++11 起)

float arg( float z );

 (4) (C++11 起)

计算复数 z 的辐角（以弧度表示）

(C++11 起)为 float 、 double 、 long double 及所有整数类型提供重载，它们被当做有零虚部的复数

参数

返回值

若无错误发生，则返回 z 在区间 (−π; π) 内的辐角。

错误和特殊情况按照函数宛如以 std::atan2(std::imag(z), std::real(z)) 实现来处理。

示例

#include <iostream>
#include <complex>
 
int main() 
{
    std::complex<double> z1(1, 0); 
    std::cout << "phase angle of " << z1 << " is " << std::arg(z1) << '\n';
 
    std::complex<double> z2(0, 1); 
    std::cout << "phase angle of " << z2 << " is " << std::arg(z2) << '\n';
 
    std::complex<double> z3(-1, 0); 
    std::cout << "phase angle of " << z3 << " is " << std::arg(z3) << '\n';
 
    std::complex<double> z4(-1, -0.0); 
    std::cout << "phase angle of " << z4 << " (the other side of the cut) is "
              << std::arg(z4) << '\n';
}

输出： 

phase angle of (1,0) is 0
phase angle of (0,1) is 1.5708
phase angle of (-1,0) is 3.14159
phase angle of (-1,-0) (the other side of the cut) is -3.14159

参阅