yuan writes:

Hi, I try to use multi index container.I have one problem. Please help me.Thanks struct TOrder { char szDate[9]; //date type  int nID; // order id int nProductID; //product id double fPrice;// int nVol;// //other member … }

The unique key of TOrder struct is szDdate and nID. How I can typedef the composite_key and the multi_index_container?

Assuming that comparison of szDate's is lexicographical, you can write something like this: struct DateCompare { bool operator()(const char* x,const char* y)const { return std::strcmp(x,y)<0; } }; typedef multi_index_container< TOrder, indexed_by< ordered_unique< composite_key< TOrder, member, member >, composite_key_compare< DateCompare, std::less<int> > >

TOrderContainer;

All of this should be explained in the tutorial. Which particular difficulties got you stuck? Thank you, Joaquín M López Muñoz Telefónica Digital