C++ Vector of classes push back error - c++

Question

I'm new in C++ , i use G++ compiler (Ubuntu 4.8.1-2ubuntu1~12.04) 4.8.1
i try to implement undirected wieghted Graph. by two classes Edges and Graph. but the compiler gives me this error
the compiler gives this error
/usr/include/c++/4.8/ext/new_allocator.h: In instantiation of 'void __gnu_cxx::new_allocator<_Tp>::construct(_Up*, _Args&& ...)
[with _Up = UNDIR_W_EDGE; _Args = {const UNDIR_W_EDGE&}; _Tp =
UNDIR_W_EDGE]':
/usr/include/c++/4.8/bits/alloc_traits.h:254:4: required from 'static typename
std::enable_ifAlloc>::_construct_helper<_Tp,
_Args>::value, void>::type std::allocator_traits<_Alloc>::_S_construct(_Alloc&, _Tp*, _Args&&
...) [with _Tp = UNDIR_W_EDGE; _Args = {const UNDIR_W_EDGE&}; _Alloc =
std::allocator; typename
std::enable_ifAlloc>::_construct_helper<_Tp,
_Args>::value, void>::type = void]'
/usr/include/c++/4.8/bits/alloc_traits.h:393:57: required from 'static decltype (_S_construct(__a, __p,
(forward<_Args>)(std::allocator_traits::construct::__args)...))
std::allocator_traits<_Alloc>::construct(_Alloc&, _Tp*, _Args&& ...)
[with _Tp = UNDIR_W_EDGE; _Args = {const UNDIR_W_EDGE&}; _Alloc =
std::allocator; decltype (_S_construct(__a, __p,
(forward<_Args>)(std::allocator_traits::construct::__args)...)) =
]'
/usr/include/c++/4.8/bits/stl_vector.h:906:34: required from 'void std::vector<_Tp, _Alloc>::push_back(const value_type&) [with _Tp
= UNDIR_W_EDGE; _Alloc = std::allocator; std::vector<_Tp, _Alloc>::value_type = UNDIR_W_EDGE]'
../src/GRAPH.h:31:5: required from 'void GRAPH::addEdge(const Edge&) [with Edge = UNDIR_W_EDGE]'
../src/main.cpp:32:13: required from here
/usr/include/c++/4.8/ext/new_allocator.h:120:4: error: no matching function for call to 'UNDIR_W_EDGE::UNDIR_W_EDGE(const UNDIR_W_EDGE&)'
{ ::new((void *)__p) _Up(std::forward<Args>(_args)...); }
The Code
GRAPH.h file
#include "vector"
template <typename Edge>
class GRAPH {
private:
// Implementation-dependent code
int Vcnt;
int Ecnt;
std::vector<std::vector< Edge > > adj;
public:
GRAPH(int x):Vcnt(x),Ecnt(0) {
adj.resize(Vcnt);
}
virtual ~GRAPH();
virtual int V() const;
virtual int E() const;
virtual void addEdge(const Edge &e){
adj[e.V()].push_back(e);
adj[e.W()].push_back(e);
Ecnt++;
};
virtual std::vector< Edge > adjIterator(int) const;
};
UNDIRWEDGE.h file
class UNDIR_W_EDGE {
int v,w;
float weight;
public:
UNDIR_W_EDGE(int v, int w, float weight);
UNDIR_W_EDGE(UNDIR_W_EDGE &);
virtual ~UNDIR_W_EDGE();
virtual int V()const;
virtual int W()const;
virtual float WEIGHT()const;
virtual int CompareTo(UNDIR_W_EDGE e)const;
};
in UNDIRWEDGE.cpp
inline int UNDIR_W_EDGE::CompareTo(UNDIR_W_EDGE e)const{
if(this->weight > e.weight) return 1;
else if (this->weight < e.weight)return -1;
else return 0;
}
in main.cpp
GRAPH<UNDIR_W_EDGE> g(10);
UNDIR_W_EDGE e(0,7,0.0);
g.addEdge(e);

Answer 1

You don't have a copy constructor for UNDIR_W_EDGE.
The copy constructor is required inside std::vector<UNDIR_W_EDGE>, as well as in CompareTo which takes its argument by value (for some reason).
You do have this:
UNDIR_W_EDGE(UNDIR_W_EDGE &);
Presumably you intended for it to be:
UNDIR_W_EDGE(const UNDIR_W_EDGE&);