how to initialise this templated pair in c++? - c++

Question

template<class V, class E>
class G
{
public:
G();
void InsertVertex(const V&);
void InsertEdge(const V&, const V&, const E& );
private:
typedef set<V,less<V> > vSet;
typedef pair<const V,V> ePair;
typedef multimap<V,V,less<V> > eSet;
typedef map<ePair,E, less<ePair> > edgeValueMap;
vSet vertices;
eSet edges;
edgeValueMap edgeVals;
};
template<class V,class E>
G<V,E>::G(){}
template<class V,class E>
void G<V,E>::InsertVertex(const V& a)
{
vertices.insert(a);
}
template<class V,class E>
void G<V,E>::InsertEdge(const V& a,const V& b, const E& val)
{
//create a pair
ePair<const V,v> e(a,b);
edges.insert(e);
edgeVals.insert(e,val);
}
int main()
{
G<char,int> g;
g.InsertVertex('a');
g.InsertVertex('b');
g.InsertVertex('c');
g.InsertEdge('a','b',1);
return 0;
}
while i create a pair using "ePair e(a,b)" i am getting error:
"template2.cpp:39:2: error: ‘G::ePair’ is not a template"
I am not sure exactly why this compile error is coming? am i missing anything here?

Answer 1

I was using make_pair to build actual map entries, it works here. But note that also the call edgeVals.insert(e,val); give error: so i modified that also:
template<class V,class E>
void G<V,E>::InsertEdge(const V& a,const V& b, const E& val)
{
//create a pair
ePair e = make_pair(a,b);
edges.insert(e);
edgeVals[e] = val;
}