C++ Map can't insert with pair

Question

Why can't I insert as shown below?

#include <map>

struct something {

} some_object;

typedef std::map<std::string, something*> list;
typedef std::pair<std::string, something*> pair;

int main()
{
    list l;
    pair p("abc", &some_object); // working fine!!!
    l.insert(p); // 17 errors

    return 0;
}

Visual studio gives me many errors and I don't understand anything of them. The first one is:

error C2784: 'bool std::operator <(const std::_Tree<_Traits> &,const std::_Tree<_Traits> &)' : could not deduce template argument for 'const std::_Tree<_Traits> &' from 'const std::string'

I can post more but I don't want to spam here. Thanks a lot for your help.

Answer 1

You need to

#include <string>

Answer 2

I would change this line:

typedef std::pair<std::string, something*> pair;

You are relaying on an implementation detail. Are you sure this wil always be true for all future version of the library? Tightly coupling your code like that is a bad idea.

Try this:

typedef list::value_type pair;

PS. 'list' would not be my first choice for the name of a type I put in the global namespace. Either put it in your own namespace or call it 'MyList'.