[Boost-users] error compiling an accumulator sample

Hi All I cannot build the following sample using accumulators. Do you know why? I used times ago an example and it worked without any problem. Can you help me with that? I have the following error error: ‘covariate1’ was not declared in this scope #include <iostream> #include #include #include #include #include #include using namespace boost::accumulators; int main() { accumulator_set > > x_acc; x_acc( 1.1, covariate1 = 2.2 ) ; return 0; }