// TestFactorial.cpp // // Factorials and Binomial Coefficients. // // Copyright Datasim Education BV 2009-2010 // Copyright John Maddock and Paul A. Bristow 2010 // Use, modification and distribution are subject to the // Boost Software License, Version 1.0. // (See accompanying file LICENSE_1_0.txt // or copy at http://www.boost.org/LICENSE_1_0.txt) #include <boost/math/special_functions/factorials.hpp> #include <boost/math/special_functions.hpp> #include <iostream> using namespace std; int main() { using namespace boost::math; // Factorials unsigned int n = 3; try { cout << "Factorial: " << factorial<double>(n) << endl; // Caution: You must provide a return type template value, so this will not compile // unsigned int nfac = factorial(n); // could not deduce template argument for 'T' // You must provide an explicit floating-point (not integer) return type. // If you do provide an integer type, like this: // unsigned int uintfac = factorial<unsigned int>(n); // you will also get a compile error, for MSVC C2338. // If you really want an integer type, you can convert from double: unsigned int intfac = static_cast<unsigned int>(factorial<double>(n)); // this will be exact, until the result of the factorial overflows the integer type. cout << "Unchecked factorial: " << boost::math::unchecked_factorial<float>(n) << endl; // Note: // unsigned int unfac = boost::math::unchecked_factorial<unsigned int>(n); // also fails to compile for the same reasons. } catch(exception& e) { cout << e.what() << endl; } // Double factorial n!! try { //cout << "Double factorial: " << boost::math::double_factorial<unsigned>(n); } catch(exception& e) { cout << e.what() << endl; } // Rising and falling factorials try { int i = 2; double x = 8; cout << "Rising factorial: " << rising_factorial(x,i) << endl; cout << "Falling factorial: " << falling_factorial(x,i) << endl; } catch(exception& e) { cout << e.what() << endl; } // Binomial coefficients try { unsigned n = 10; unsigned k = 2; // cout << "Binomial coefficient: " << boost::math::binomial_coefficient<unsigned>(n,k) << endl; } catch(exception& e) { cout << e.what() << endl; } return 0; } /* Output: factorial_example.vcxproj -> J:\Cpp\MathToolkit\test\Math_test\Release\factorial_example.exe Factorial: 6 Unchecked factorial: 6 Rising factorial: 72 Falling factorial: 56 */