When to use pointer template parameters?

I created a templated class which searches for a path between 2 points in a graph. The template parameter takes in a class representing the graph.

template <class graph_type>
class Graph_PathSearch
{
public:
Graph_PathSearch(&graph_type G, int startIndex, int endIndex);
};


The graph object is declared as a pointer.

NavGraph* m_pGraph;
m_pGrapn = new NavGraph(true);


I then instantiated the path search using this statement:

Graph_PathSearch<NavGraph*> StartSearch(*m_pGraph,startNode,destNode);


But the compiler produced a long string of compile errors. However, when I changed the template parameter from <NavGraph*> to <NavGraph>, there were no more compile errors.

I would like to know when is the right time to use a pointer as a template parameter, since the graph is declared as a pointer but using a pointer as a template parameter is incorrect in this case?

Quote:

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Originally Posted by ZhiYi

I then instantiated the path search using this statement:

Graph_PathSearch<NavGraph*> StartSearch(*m_pGraph,startNode,destNode);


But the compiler produced a long string of compile errors. However, when I changed the template parameter from <NavGraph*> to <NavGraph>, there were no more compile errors.

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Maybe the errors were legitimate. It's impossible to know if you don't post your entire code.

Second, if the pointer is typedef'ed, it may resolve some of the errors:

Code:

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typedef  NavGraph* NavGraphPtr;

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And then use NavGraphPtr.

Regards,

Paul McKenzie

Quote:

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But the compiler produced a long string of compile errors. However, when I changed the template parameter from <NavGraph*> to <NavGraph>, there were no more compile errors.

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Based on the code you posted, you call the function with NavGraph* as the template parameter, but in first argument to that function you dereference the pointer m_pGraph, hence you're actually passing a NavGraph object to the function.