[RESOLVED] Declara object type based on run time template parameter

[Peter_APIIT]

Hello to all expert C++ programmer,

template <typename T, class edgeType = edge>
class graph
{	
public:
/*
  shared_ptr's template parameter is object 
  and not pointer to object
*/
	typedef boost::shared_ptr<vertex<T> > 
		vertexPtr;
private:

	std::vector<vertexPtr> allVertex;

I want that when different type of edgeType is supplied, then i want instantiated different type of vertexPtr.

I have two type of edgeType, one is edge(undirected) and arcs(Directed).

Whenever user supplied, graph<int, arcs> DAG;, then in the

typedef boost::shared_ptr<arcs> arcsPtr;
typedef boost::shared_ptr<vertex<T, arcsPtr> > vertexPtr;

should have arcsPtr.

Then, if user graph<int> supplied this, then default vertexPtr should be used.

I hope this make sense to you all.

Traits or CRTP or any design patterns is greatly appreciated by me.

The purpose of this question is to declare a graph class template that works with directed and undirected class based on template parameter.

graph<int> grp -- Undirected;
graph(int, arcs> -- directed;


Thanks for your help.

[Codeplug]

typedef boost::shared_ptr<edgeType> edgeTypePtr;
typedef boost::shared_ptr<vertex<T, edgeTypePtr> > vertexPtr;

I think that's what you want.

gg

[Peter_APIIT]

Let me rephrase the question.

If i supplied graph<int>, then in graph 
     typedef  boost::shared_ptr<vertex<T> > vertexPtr;
     std::vector<vertexPtr> allVertex;(Undirected graph)
else 
   graph<int, arcs>
   then i need 
   typedef  boost::shared_ptr<vertex<T, arcs> > arcsVertexPtr;
    std::vector<arcsVertexPtr> allVertex;(directed graph)

I hope this make more sense.

Thanks.

[Codeplug]

Ah. Then you can use a traits-type template with specialization to "choose" the appropriate type:

template <typename T, typename edgeType>
struct edgeTypeTraits; // no impl. - just for specialization

template <typename T>
struct edgeTypeTraits<T, edge> // specialized for edge
{
    typedef boost::shared_ptr<vertex<T> > vertexPtr_t;
    typedef std::vector<vertexPtr_t>      allVertex_t;
};//edgeTypeTraits<T, edge>

template <typename T>
struct edgeTypeTraits<T, arcs> // specialized for arcs
{
    typedef boost::shared_ptr<vertex<T, arcs> > vertexPtr_t;
    typedef std::vector<vertexPtr_t>            allVertex_t;
};//edgeTypeTraits<T, edge>

template <typename T, typename edgeType = edge>
struct graph
{
    typedef typename edgeTypeTraits<T, edgeType>::vertexPtr_t vertexPtr_t;
    typedef typename edgeTypeTraits<T, edgeType>::allVertex_t allVertex_t;

    vertexPtr_t m_vp;
    allVertex_t m_av;
};//graph

gg

[Peter_APIIT]

I have did what you show but but this doesn't clear it the problem due to numerous compilation problem.

My code:

#ifndef EDGETYPETRAITS_H
#define EDGETYPETRAITS_H


#include <boost/shared_ptr.hpp>
#include "Arcs.h"
#include "Edge.h"


template <typename T, typename link = edgePtr>
class vertex;


// Base class no definition
template <typename T, typename edgeType>
class edgeTypeTrais;


// Partial Specialization
template <typename T>
class edgeTypeTrais<T, edge> 
{
public:
	typedef boost::shared_ptr<vertex<int> > vertexPtr; 
	typedef std::vector<vertexPtr> allVertexVector;
};


// Partial Specialization
template <typename T>
class edgeTypeTraits<T, arcs> ---> [bold]Error[/bold]
{
public:
	typedef boost::shared_ptr<vertex<int, arcs> > vertexPtr; 
	typedef std::vector<vertexPtr> allVertexVector;
};

#endif

The error appear at second edgeTypeTraits class.

If i uncomment the second edgeTypeTraits class,

error appear at here

typedef typename edgeTypeTraits<T, edgeType::allVertexVector allVertexVector;

allVertexVector allVertex;

error C2143: syntax error : missing ';' before '<'
error C2059: syntax error : '<'
error C2143: syntax error : missing ';' before '{'
error C2447: '{' : missing function header (old-style formal list?)
error C2977: 'edgeTypeTraits' : too many template arguments
error C2039: 'vertexPtr' : is not a member of 'edgeTypeTraits'
error C2146: syntax error : missing ';' before identifier 'vertexPtr'
error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
error C2868: 'graph<T,edgeType>::vertexPtr' : illegal syntax for using-declaration; expected qualified-name
warning C4346: 'edgeType::allVertexVector' : dependent name is not a type
error C2146: syntax error : missing ',' before identifier 'allVertexVector'
error C2065: 'allVertexVector' : undeclared identifier
error C2143: syntax error : missing '>' before ';'
error C2208: 'edgeTypeTraits' : no members defined using this type
error C2146: syntax error : missing ';' before identifier 'allVertex'
Error 16 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int d:\c++\data structure\graph\graph\graph.h 31
error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
error C2977: 'edgeTypeTraits' : too many template arguments
Error 19 error C2955: 'edgeTypeTraits' : use of class template requires template argument list
error C2027: use of undefined type 'edgeTypeTraits'
error C2146: syntax error : missing ';' before identifier 'vertexPtr'
error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
error C2602: 'graph<T>::vertexPtr' is not a member of a base class of 'graph<T>'
error C2868: 'graph<T>::vertexPtr' : illegal syntax for using-declaration; expected qualified-name d:\c++\data structure\graph\graph\graph.h 26
error C2039: 'allVertexVector' : is not a member of 'edge'
Error 26 error C2146: syntax error : missing ',' before identifier 'allVertexVector' d:\c++\data structure\graph\graph\graph.h 30
error C2143: syntax error : missing '>' before ';'
error C2208: 'edgeTypeTraits' : no members defined using this type0
error C2146: syntax error : missing ';' before identifier 'allVertex' d:\c++\data structure\graph\graph\graph.h 31
Error 30 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

MS VS 2005

My complete code:

#ifndef ARCS_H
#define ARCS_H


#include <string>
#include <boost/shared_ptr.hpp>


class arcs
{
private:
	int weightage;
	std::string toVertex;

public:
	arcs();
	~arcs();
};
#endif

#include <algorithm>
#include <string>
#include "Arcs.h"


// =============================================
arcs::arcs() : weightage(int (0)), toVertex(std::string(""))
{
}
// =============================================
arcs::~arcs()
{
}

#ifndef EDGE_H
#define EDGE_H

#include <string>

/* arcs is directed edge
   edge is undirected edge 
*/

class edge
{
private:
	// Path's cost
	int weightage;
	std::string firstVertexID;
	std::string secondVertexID;

	/*	An edge in an undirected graph 
		is a set of two vertices
		
		An edge is placed twice, once for A->B
		B->A
	
	*/

public:
	edge();
	edge(int);
	edge(const edge&);
	edge& operator=(const edge&);

	void setWeightage(int);
	int getWeightage();

	void setFirstVertexID(const std::string&);
	void setSecondVertexID(const std::string&);

	std::string getFirstVertexID();
	std::string getSecondVertexID();

	~edge();
};

#endif

#include <algorithm>
#include <string>
#include "Edge.h"

// =============================================
edge::edge() : weightage(0), 
		firstVertexID(std::string("")), 
		secondVertexID(std::string(""))
{
}
// =============================================
edge::edge(int myWeightage) 
	: weightage(myWeightage), 
		firstVertexID(std::string("")), 
		secondVertexID(std::string("")) 
{
}
// =============================================
edge::edge(const edge& that) 
	: weightage(that.weightage), 
		firstVertexID(std::string(that.firstVertexID)), 
		secondVertexID(std::string(that.secondVertexID)) 
{
}
// =============================================
edge& edge::operator=(const edge& that)
{
	if (this != &that)
	{
		edge tempEdge(that.weightage);
		tempEdge.firstVertexID = that.firstVertexID;
		tempEdge.secondVertexID = that.secondVertexID;

		std::swap(this->weightage, 
			tempEdge.weightage);
	}
	return *this;
}
// =============================================
edge::~edge()
{
}
// =============================================
void edge::setWeightage(int userWeightage)
{
	weightage = userWeightage;
}
// =============================================
int edge::getWeightage()
{
	return this->weightage;
}
// =============================================
void edge::setFirstVertexID(const std::string& userVertexID)
{
	firstVertexID = userVertexID;
}
// =============================================
void edge::setSecondVertexID(const std::string& userVertexID)
{
	secondVertexID = userVertexID;
}
// =============================================
std::string edge::getFirstVertexID()
{
	return firstVertexID;
}
// =============================================
std::string edge::getSecondVertexID()
{
	return secondVertexID;
}
// =============================================


#ifndef VERTEX_H
#define VERTEX_H


#include <vector>
#include <string>
#include <boost/shared_ptr.hpp>

#include "Edge.h"

typedef boost::shared_ptr<edge> edgePtr;



template <typename T, typename link = edgePtr>
class vertex
{
public:

	typedef boost::shared_ptr<vertex<T> > vertexPtr;

private:
	// Number of edge incident from this vertex
	int degree;
	// Distance from this vertex to another vertex
	int fromDistance; 
	// Vertex name
	std::string vertexID;
	// Vertex information
	T element;
	
	/* 
		This used to represent/store all edges 
		incident(attach/link) from/to this vertex
	*/	
	std::vector<link> incidentEdge;
	std::vector<vertexPtr> incidentVertex;

	
	
public:
	
	vertex();
	vertex(const T& );

	void decreaseDegree();

	void setDegree();
	void setDegree(int);

	void setFromDistance(int);
	void setVertexID(const std::string& );
	void setElement(const T&);
	void setIncidentEdge(boost::shared_ptr<edge>& );
	void setIncidentVertex(boost::shared_ptr<vertex>& );
	
	void deleteEdge(int);
	void deleteVertex(int);

	int getDegree();
	int getFromDistance();
	const std::string getVertexID();
	const T getElement();
	std::vector<link>& getIncidentEdge();
	std::vector<typename vertex<T>::vertexPtr>& getIncidentVertex();

	~vertex();
};

// =============================================
template <typename T, typename link>
vertex<T, link>::vertex() : degree(0),
				fromDistance(0)
				vertexID(std::string("")), 
				element(T()),
				incidentEdge(vector<link>()), 
				incidentVertex(vector<vertexPtr>())
{
}
// =============================================
template <typename T, typename link>
vertex<T, link>::vertex(const T& info) : degree(0), 
				fromDistance(0), vertexID(std::string()), 
				element(info),
				incidentEdge(vector<link>()), 
				incidentVertex(vector<vertexPtr>())
{
}
// =============================================
template <typename T, typename link>
vertex<T, link>::~vertex()
{
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::decreaseDegree()
{
	--degree;
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::setDegree()
{
	++degree;
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::setFromDistance(int userDistance)
{
	fromDistance = userDistance;
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::setDegree(int myDegree)
{
	degree = myDegree;
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::setVertexID(const std::string& vertexName)
{
	vertexID = vertexName;
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::setElement(const T& info)
{
	element = info;
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::setIncidentEdge(boost::shared_ptr<edge>& userEdge)
{
	incidentEdge.push_back(userEdge);
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::setIncidentVertex(boost::shared_ptr<vertex>& userVertex)
{
	incidentVertex.push_back(userVertex);
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::deleteEdge(int position)
{
	incidentEdge.erase(incidentEdge.begin() + position);
}
// =============================================
template <typename T, typename link>
void vertex<T, link>::deleteVertex(int position)
{
	incidentVertex.erase(incidentVertex.begin() + position);
}
// =============================================
template <typename T, typename link>
int vertex<T, link>::getDegree()
{
	return this->degree;
}	
// =============================================
template <typename T, typename link>
int vertex<T, link>::getFromDistance()
{
	return this->fromDistance;
}
// =============================================
template <typename T, typename link>
const std::string vertex<T, link>::getVertexID()
{
	return this->vertexID;
}
// =============================================
template <typename T, typename link>
const T vertex<T, link>::getElement()
{
	return this->element;
}
// =============================================
template <typename T, typename link>
std::vector<link>& vertex<T, link>::getIncidentEdge()
{
	return this->incidentEdge;
}
// =============================================
template <typename T, typename link>
std::vector<typename vertex<T>::vertexPtr>& vertex<T, link>::getIncidentVertex()
{
	return this->incidentVertex;
}


#endif

#ifndef GRAPH_H
#define GRAPH_H

#include <vector>
#include <queue>
#include <limits>

#include "EdgeTypeTraits.h"

// Forward Declaration minimize file dependecies
class edge;

template <typename T, typename link = edgePtr>
class vertex;



template <typename T, class edgeType = edge>
class graph
{	
public:
/*
  shared_ptr's template parameter is object 
  and not pointer to object
*/
	typedef typename edgeTypeTraits<T, edgeType>::vertexPtr vertexPtr;

private:

	typedef typename edgeTypeTraits<T, edgeType::allVertexVector allVertexVector;
	allVertexVector allVertex;
};

#endif

Thanks.

[Codeplug]

>> edgeTypeTrais
>> edgeTypeTraits
Spelling

>> typedef typename edgeTypeTraits<T, edgeType::allVertexVector allVertexVector;
Syntax. Missing a '>'

gg

[Peter_APIIT]

Good eyes spot.

Thanks.