Factorial: Difference between revisions

=={{header|C}}==

=== Iterative ===

<c>

int factorial(int n)

{

int result = 1;

for (int i = 1; i <= n; ++i)

result *= i;

return result;

}

</c>

=== Recursive ===

<c>

int factorial(int n)

{

if (n == 0)

return 1;

else

return n*factorial(n-1);

}

</c>

=={{header|C++}}==

The C versions work unchanged with C++, however, here is another possibility using the STL and boost:

<cpp>

#include <boost/config.hpp>

#include <boost/counting_iterator.hpp>

int factorial(int n)

{

boost::counting_iterator_generator<int>::type first(1), last(n+1); // last is one-past-end

return std::accumulate(first, last, 1, std::multiplies<int>());

}

</cpp>