Question

I have a structure

struct dbdetails
{
    int id;
    string val;
};

I need a data structure in C++ that can hold structure variable with a sort capability. Is it possible? I was looking at vector, which can hold structure variable, but I will not be able to sort it based on id, because it is a structure member. Any suggestions?

Answer 1

You need a custom functor for comparing your tries. This should do the trick:

#include <algorithm>
#include <vector>
// try is a keyword. renamed
struct sorthelper : public std::binary_function<try_, try_, bool>
{
    inline bool operator()(const try_& left, const try_& right)
    {   return left.id < right.id;  }
};

...
std::vector<try_> v;
// fill vector 
std::sort(v.begin(), v.end(), sorthelper());
...

Please feel free to ask if you have any follow-up questions. Do you possess the Stroustrup book?

Edit: Suggestion of Matteo:

struct try_
{
    int id;
    string val;
    bool operator<(const try_& other) const
        {return id < other.id;}

}; // no s here plz.

...
std::vector<try_> v;
// fill vector 
std::sort(v.begin(), v.end());
...