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C++ Cookbook
book

C++ Cookbook

by D. Ryan Stephens, Christopher Diggins, Jonathan Turkanis, Jeff Cogswell
November 2005
Beginner to intermediate content levelBeginner to intermediate
594 pages
16h 23m
English
O'Reilly Media, Inc.
Content preview from C++ Cookbook

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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Publisher Resources

ISBN: 0596007612Supplemental ContentErrata Page