more/getting_started/detail/build-simple-head.rst

Build a Simple Program Using Boost

To keep things simple, let's start by using a header-only library. The following program reads a sequence of integers from standard input, uses Boost.Lambda to multiply each number by three, and writes them to standard output:

#include <boost/lambda/lambda.hpp>
#include <iostream>
#include <iterator>
#include <algorithm>

int main() 
{
    using namespace boost::lambda;
    typedef std::istream_iterator<int> in;

    std::for_each( 
        in(std::cin), in(), std::cout << (_1 * 3) << " " );
}

Copy the text of this program into a file called example.cpp.