Insert into map with pair as key and list as value

Question

I have the following map in C++:

typedef std::pair<int, int> iPair;

std::map< iPair, std::list< iPair > > world;

I want to make insert and update of the map for a pair(u,v) -> push back in list:

 iPair src = make_pair(p1, u1);
 iPair dst = make_pair(p2, u2);
 map[src].push_back(dst);

I get a compiling error when trying to access map[src]:

error: missing template arguments before ‘[’ token

Not `map[src]`, but `world[src]` - that's the name of your variable, isn't it? — jlahd, Aug 19 '17 at 15:20
Chances are you have `using namespace std;` which is causing your use of `map` to be resolved to `std::map` which requires a template parameter like the error says. — Gambit, Aug 19 '17 at 15:22

score 4 · Accepted Answer · answered Aug 19 '17 at 15:20

4

You need world[src] since that is the name of your map variable, that should work.

answered Aug 19 '17 at 15:20

Cuber

1 Answers1