Re: [Boost-users] How to use multi index container?

Subject: Re: [Boost-users] How to use multi index container?
From: Joaquin M Lopez Munoz (joaquin_at_[hidden])
Date: 2013-10-18 08:09:41

yuan <yuanzhan <at> qq.com> writes:

> 
> Hi,
> I try to use multi index container.I have one problem.
> Please help me.Thanks
> struct TOrder
> {
>   char szDate[9]; //date type
>  Â 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<TOrder,char[9],&TOrder::szDate>,
        member<TOrder,int,&TOrder::nID>
      >,
      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