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- // 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
- */
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