ns问题请教

刚开始学习ns，看了一些相关的代码，在看无线路由协议aodv时
遇到一点问题，请大虾指教。
static class AODVclass : public TclClass {
public:
        AODVclass() : TclClass("Agent/AODV") {}
        TclObject* create(int argc, const char*const* argv) {
          assert(argc == 5);
          //return (new AODV((nsaddr_t) atoi(argv[4])));
          return (new AODV((nsaddr_t) Address::instance().str2addr(argv[4])));
        }
} class_rtProtoAODV;
为什么这里的create要带参数，是因为
AODV::AODV(nsaddr_t id)这个构造函数要带参数吗？
另外，为什么create的参数要是5个，其它几个参数是什么呢？这个
在哪个文件中呢？

— argv[0] contains the name of the object.
— argv[1...3] contain $self, $class, and $proc.Since create is called through the instance procedure
create-shadow, argv[3] contains create-shadow.
— argv[4] contain any additional arguments (passed as a string) provided by the user.
见ns-manual p29