Add new algorithm boost::power, which raises a number to an integer power

include/boost/algorithm/algorithm.hpp

@@ -0,0 +1,50 @@
+/* 
+   Copyright (c) Marshall Clow 2014.
+
+   Distributed under 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)
+
+ Revision history:
+    2 Dec 2014 mtc First version; power
+   
+*/
+
+/// \file algorithm.hpp
+/// \brief Misc Algorithms
+/// \author Marshall Clow
+///
+
+#ifndef BOOST_ALGORITHM_HPP
+#define BOOST_ALGORITHM_HPP
+
+#include <boost/utility/enable_if.hpp> // for boost::disable_if
+
+namespace boost { namespace algorithm {
+
+/// \fn power ( T x, Integer n )
+/// \return the value "x" raised to the power "n"
+/// 
+/// \param x     The value to be exponentiated
+/// \param n     The exponent
+///
+//	\remark Taken from Knuth, The Art of Computer Programming, Volume 2:
+//		Seminumerical Algorithms, Section 4.6.3
+template <typename T, typename Integer>
+T power (T x, Integer n) {
+	T y = 1; // Should be "T y{1};" 
+	if (n == 0) return y;
+	while (true) {
+		if (n % 2 == 1) {
+			y = x * y;
+			if (n == 1)
+				return y;
+			}
+		n = n / 2;
+		x = x * x;
+		}
+	return y;
+	}
+
+}}
+
+#endif // BOOST_ALGORITHM_HPP