[Boost-users] [Boost.StringAlgo] How to insert substr into str

Dear All, what is the elegant/right way to insert some substr into the given str? For example: // ------------------------------------------------------- ... std::string str("xyz_123_abc_xyyz_a1b"); std::string mark("abc"); std::string substr("$$$"); iterator_rangestd::string::type> it1 = boost::find_first(str, mark); ... // ------------------------------------------------------- I want to insert substr ("$$$") after mark ("abc") if the mark exists in the str. That is, the result in the example above should be: "xyz_123_abc$$$_xyyz_a1b" Thank you in advance!