Before I proceed with the code implementation, I need to find the error that this program initiates. I can't figure out the solution, I guess thats what happens after not using c++ for 4 years...

The compilation errors I'm getting are all of this type (11 of them):
Error 9 error C2784: 'bool std::operator <(const std::vector<_Ty,_Alloc> &,const std::vector<_Ty,_Alloc> &)' : could not deduce template argument for 'const std::vector<_Ty,_Alloc> &' from 'const Node' c:\program files\microsoft visual studio 8\vc\include\functional 143

If anyone could help me, I would be very grateful, since I cant figure ot out for a long time...

#include "stdafx.h"
#include <deque>
#include <list>
#include <queue>
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
#include <set>
using namespace std;

char file_name[15];
char links_file[15];
char alg[15];
char with_list[15];
char new_name[15];
int depth;
long idstart,idgoal;

class Action
{ 
	public:

	long start_node;
	long end_node;
	int distance; 
	int one_way;
	string road;

	Action();
	Action(long sn, long en, int dist, int ow, string r)
	{
		start_node=sn;
		end_node=en;
		distance=dist;
		one_way=ow;
		road=r;
	}
};

class Node
{
public:
	long state;
	int path_cost;
	Node();
	Node(long s,int p_c)
	{
		state=s;
		path_cost=p_c;
	}
};

class Problem
{
public:
 long initial_node;
 long final_node;
 int path_cost;

	bool GoalTest(Node node)
	{
		if(node.state==final_node)
			return true;
		else return false;
	}
	Problem();
	Problem(long in, long fn)
	{
	initial_node=in;
	final_node=fn;
	path_cost=0;
	
	}
bool bfs(Problem pbm);


};


Node ChildNode(Problem pbm, Node n, Action a)
{

}

void assign_value(Node n1,Node n2)
{
	n1.path_cost=n2.path_cost;
	n1.state=n2.state;
}

bool cmpNodes(Node n1, Node n2)
{
	if((n1.path_cost==n2.path_cost) && (n1.state==n2.state))
		return true;
	else return false;
}


int _tmain(int argc, _TCHAR* argv[])
{
	list<Action> actions;
	list<Action>::iterator j;
	int frontier_no=0;
	
	queue<Node,list<Node> > frontier;
	set<Node> explored;
	char command_line[150];
	int acts=0;

	if(argc==8)
		{
			printf("Enter: file name, links file, algorithm name(bfs/dfs/astar), closed list(Y/N), depth to search, id of the starting node, id of the goal node, name of new file: ");
			scanf("%s",command_line); //read the name of the file
			sscanf(command_line,"%s %s %s %s %d %l %l %s",file_name,links_file,alg,with_list,depth,idstart,idgoal,new_name);
			
			string start_node;
			string end_node;
			string distance; 
			string one_way;
			string road;
			string line;
			int no_links;
			int line_no;
			ifstream fp(links_file);

			if (fp.is_open())
			  {
				while (!fp.eof())
				{
				  getline (fp,line);
				  line_no++;
				}
				fp.close();
			  }
			
			
			if (fp.is_open())
			{
					while (!fp.eof())
					{
						  getline(fp,line);
						  istringstream iss(line);
						  iss >> start_node;
						  iss>>end_node;
						  iss>>distance;
						  iss>>one_way;
						  iss>>road;
						  iss>>line;
						Action a;
						a.distance=atoi(distance.c_str());
						a.end_node=atol(end_node.c_str());
						a.one_way=atoi(one_way.c_str());
						a.road=road;
						a.start_node=atol(start_node.c_str());
						//=new Action(atol(start_node.c_str()),atol(end_node.c_str()),atoi(distance.c_str()),atoi(one_way.c_str()),road);
						actions.push_back(a);
						acts++;
						 
					}
					fp.close();
				}
					else cout << "Unable to open file";
			

			Problem problem;
			problem.final_node=idgoal;
			problem.initial_node=idstart;
			//=new Problem(idstart,idgoal);
			Node child;
			Node node;
			node.path_cost=problem.path_cost;
			node.state=problem.initial_node;
			//=new Node((*problem).initial_node,(*problem).path_cost);
			if(problem.GoalTest(node)) return (1);
			
		
			bool in_queue=false;

			while(1)
			{
				if(frontier.empty()) return -1;
				assign_value(node,frontier.front());
				explored.insert(node);

				
				for(j=actions.begin();j!=actions.end();j++)
				{
				assign_value(child,ChildNode(problem,node,actions.front()));
				int i;
					for( i=0;i<acts;i++)
						{
							in_queue=cmpNodes(child,frontier.front());
							Node n;
							assign_value(n,frontier.front());
							frontier.push(n);
							frontier.pop();
							if(in_queue)
								break;
								
						}
					set<Node>::iterator it;
					it=explored.find(child);
					if(it!=explored.end()&&!in_queue)
					{
						
							if(problem.GoalTest(child))
								return (1);
							frontier.push(child);
					}
					in_queue=false;
				}
			}
			
			
		}
	return 0;
}

From the looks of the error you're getting, I'd say you probably need to create an override for the operator< to allow two instances of your node class to be compared.

I've not really looked through your code too much, I've only given it a brief once over so I'm not 100% on what you're doing, but I'd guess that you need to be adding something like this:

bool operator<(const Node &n1, const Node &n2)
{
	return n1.path_cost < n2.path_cost;
}

If that's not exactly what you want, you might just want to slap the code from cmpNodes() in there. Either way, you should put your own code in there to compare two Nodes. But one thing's for sure, the compiler is almost certainly complaining about the lack of an operator< override!

I did notice a few other things during my brief sweep of your code. I noticed with your usage of printf, scanf and sscanf, you're mixing some outdated and potentially unsafe C stuff with C++ there. Could be worth updating. It also looks as if the variable 'line_no' is uninitialised at line 124 before it is incremented at line 132. Another potential bug!

You should also be getting an error about the ChildNode function as it doesn't return anything ATM. But I'm guessing that's because you haven't got round to implementing that yet!

Cheers for now,
Jas.

Thanks a lot! This was very helpful!

From the looks of the error you're getting, I'd say you probably need to create an override for the operator< to allow two instances of your node class to be compared.

I've not really looked through your code too much, I've only given it a brief once over so I'm not 100% on what you're doing, but I'd guess that you need to be adding something like this:

bool operator<(const Node &n1, const Node &n2)
{
	return n1.path_cost < n2.path_cost;
}

If that's not exactly what you want, you might just want to slap the code from cmpNodes() in there. Either way, you should put your own code in there to compare two Nodes. But one thing's for sure, the compiler is almost certainly complaining about the lack of an operator< override!

I did notice a few other things during my brief sweep of your code. I noticed with your usage of printf, scanf and sscanf, you're mixing some outdated and potentially unsafe C stuff with C++ there. Could be worth updating. It also looks as if the variable 'line_no' is uninitialised at line 124 before it is incremented at line 132. Another potential bug!

You should also be getting an error about the ChildNode function as it doesn't return anything ATM. But I'm guessing that's because you haven't got round to implementing that yet!

Cheers for now,
Jas.

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