Mathematica++ a C++ library that speaks Mathematica

symbol x("x");
value  res;
std::string method = "Newton";

shell << Values(FindRoot(ArcTan(1000 * Cos(x)), List(x, 1, 2),  Rule("Method") = method));
shell >> res;
std::vector<double> results = cast<std::vector<double>>(res);
std::cout << results[0] << std::endl; // Prints 10.9956