11.18. Working with Polar Coordinates
Problem
You want to represent and manipulate polar coordinates.
Solution
The complex
template from the <complex>
header
provides functions for conversion to and from polar coordinates. Example 11-34 shows how you can use the
complex template class to represent and manipulate polar coordinates.
Example 11-34. Using complex template class to represent polar coordinates
#include <complex> #include <iostream> using namespace std; int main() { double rho = 3.0; // magnitude double theta = 3.141592 / 2; // angle complex<double> coord = polar(rho, theta); cout << "rho = " << abs(coord) << ", theta = " << arg(coord) << endl; coord += polar(4.0, 0.0); cout << "rho = " << abs(coord) << ", theta = " << arg(coord) << endl; }
Example 11-34 produces the following output:
rho = 3, theta = 1.5708 rho = 5, theta = 0.643501
Discussion
There is a natural relationship between polar coordinates and complex numbers. Even
though the two are somewhat interchangeable, it is generally not a good idea to use the
same type to represent different concepts. Since using the complex
template to represent polar coordinates is inelegant, I have provided
a polar coordinate class that is more natural to use in Example 11-35.
Example 11-35. A polar coordinate class
#include <complex> #include <iostream> using namespace std; template<class T> struct BasicPolar { public: typedef BasicPolar self; // constructors BasicPolar() : m() { } BasicPolar(const self& x) : m(x.m) { } BasicPolar(const ...
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