In this assignment we are not allowed to make changes to Graph.h it cannot be changed! I need help with the Graph.cpp and the Driver.cpp.

Your assignment is to implement a sparse adjacency matrix data structure Graph that is defined in the header file Graph.h. The Graph class provides two iterators. One iterator produces the neighbors for a given vertex. The second iterator produces each edge of the graph once.

Additionally, you must implement a test program that fully exercises your implementation of the Graph member functions. Place this program in the main() function in a file named Driver.cpp.

The purpose of an iterator is to provide programmers a uniform way to iterate through all items of a data structure using a forloop. For example, using the Graph class, we can iterate thru the neighbors of vertex 4 using:

Graph::NbIterator nit ; for (nit = G.nbBegin(4); nit != G.nbEnd(4) ; nit++) { cout << *nit << " " ; } cout << endl ;

The idea is that nit (for neighbor iterator) starts at the beginning of the data for vertex 4 in nz and is advanced to the next neighbor by the ++ operator. The for loop continues as long as we have not reached the end of the data for vertex 4. We check this by comparing against a special iterator for the end, nbEnd(4). This requires the NbIterator class to implement the ++, !=and * (dereference) operators.

Similarly, the Graph class allows us to iterate through all edges of a graph using a for loop like:

Graph::EgIterator eit ; tuple edge ; for (eit = G.egBegin() ; eit != G.egEnd() ; eit++) { edge = *eit ; // get current edge cout << "(" << get<0>(edge) << ", " << get<1>(edge) << ", " << get<2>(edge) << ") " ; } cout << endl ;

Note that each edge should be printed only once, even though it is represented twice in the sparse adjacency matrix data structure.

Since a program may use many data structures and each data structure might provide one or more iterators, it is common to make the iterator class for a data structure an inner class. Thus, in the code fragments above, nit and eit are declared asGraph::NbIterator and Graph::EgIterator objects, not just NbIterator and EgIterator objects.

Here are the specifics of the assignment, including a description for what each member function must accomplish.

Requirement: your implementation must dynamically resize the m_nz and m_ci arrays. See the descriptions of Graph(constructor) and addEdge, below.

Requirement: other than the templated tuple class, you must not use any classes from the Standard Template Library or other sources, including vector and list. All of the data structure must be implemented by your own code.

Requirement: your code must compile with the original Graph.h header file. You are not allowed to make any changes to this file. Yes, this prevents you from having useful helper functions. This is a deliberate limitation of this project. You may have to duplicate some code.

Requirement: a program fragment with a for loop that uses your NbIterator must have worst case running time that is proportional to the number of neighbors of the given vertex.

Requirement: a program fragment with a for loop that uses your EgIterator must have worst case running time that is proportional to the number of vertices in the graph plus the number of edges in the graph.

Graph.h:

#ifndef _GRAPH_H_ #define _GRAPH_H_ #include  // for throwing out_of_range exceptions #include  // for tuple template class Graph { public: // Graph constructor; must give number of vertices Graph(int n); // Graph copy constructor Graph(const Graph& G); // Graph destructor ~Graph(); // Graph assignment operator const Graph& operator= (const Graph& rhs); // return number of vertices int numVert(); // return number of edges int numEdge(); // add edge between u and v with weight x void addEdge(int u, int v, int x); // print out data structure for debugging void dump(); // Edge Iterator inner class class EgIterator { public: // Edge Iterator constructor; indx can be used to // set m_indx for begin and end iterators. EgIterator(Graph *Gptr = nullptr, int indx = 0); // Compare iterators; only makes sense to compare with // end iterator bool operator!= (const EgIterator& rhs); // Move iterator to next printable edge void operator++(int dummy); // post increment // return edge at iterator location std::tuple operator*(); private: Graph *m_Gptr; // pointer to associated Graph int m_indx; // index of current edge in m_nz int m_row; // corresponding row of m_nz[m_indx] }; // Make an initial edge Iterator EgIterator egBegin(); // Make an end iterator for edge iterator EgIterator egEnd(); // Neighbor Iterator inner class class NbIterator { public: // Constructor for iterator for vertices adjacent to vertex v; // indx can be used to set m_indx for begin and end iterators NbIterator(Graph *Gptr = nullptr, int v = 0, int indx = 0); // Compare iterators; only makes sense to compare with // end iterator bool operator!=(const NbIterator& rhs); // Move iterator to next neighbor void operator++(int dummy); // Return neighbor at current iterator position int operator*(); private: Graph *m_Gptr; // pointer to the associated Graph int m_row; // row (source) for which to find neighbors int m_indx; // current index into m_nz of Graph }; // Make an initial neighbor iterator NbIterator nbBegin(int v); // Make an end neighbor iterator NbIterator nbEnd(int v); private: int *m_nz; // non-zero elements array int *m_re; // row extent array int *m_ci; // column index array int m_cap; // capacity of m_nz and m_ci int m_numVert; // number of vertices int m_numEdge; // number of edges }; #endif