Subject: [Boost-commit] svn:boost r67364 - trunk/libs/math/example
From: pbristow_at_[hidden]
Date: 2010-12-20 10:33:53
Author: pbristow
Date: 2010-12-20 10:33:46 EST (Mon, 20 Dec 2010)
New Revision: 67364
URL: http://svn.boost.org/trac/boost/changeset/67364
Log:
New factorial example
Added:
trunk/libs/math/example/factorial_example.cpp (contents, props changed)
Added: trunk/libs/math/example/factorial_example.cpp
==============================================================================
--- (empty file)
+++ trunk/libs/math/example/factorial_example.cpp 2010-12-20 10:33:46 EST (Mon, 20 Dec 2010)
@@ -0,0 +1,96 @@
+// 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
+
+*/
+