A graph class to do bfs and other algorithms on the graph.

graph.cpp

/*
  Copyright (c) 2016 Tanay PrabhuDesai

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
*/

#include <iostream>
#include <map>
#include <string>
#include <unordered_set>
#include <queue>
#include <list>

class UndirectedGraph {
private:
    std::map<std::string, std::map<std::string, int> > edge;
    std::unordered_set<std::string> vertex_name;
public:
    void addVertex(std::string v) {
        vertex_name.insert(v);
    }

    void addEdge(std::string v1, std::string v2, int w) {
        if(vertex_name.find(v1) == vertex_name.end())vertex_name.insert(v1);
        if(vertex_name.find(v2) == vertex_name.end())vertex_name.insert(v2);
        edge[v1][v2] = w;
        edge[v2][v1] = w;
    }

    std::list<std::string> bfs(std::string v1, std::string v2, int &cost) {
        std::list<std::string> res;
        std::queue<std::string> q;
        std::map<std::string, std::string> m;
        std::map<std::string, bool> visited;
        q.push(v1);
        std::string v = "";
        while(!q.empty()) {
            v = q.front();
            q.pop();
            if(v == v2) {
                break;
            }
            visited[v] = true;
            for( auto i = vertex_name.begin() ; i != vertex_name.end() ; ++i ) {
                if(edge[v][*i] > 0 && visited[*i] != true) {
                    q.push(*i);
                    m[*i] = v;
                }
            }
        }
        v = v2;
        cost = 0;
        res.push_front(v);
        while(v != v1) {
            cost += edge[v][m[v]];
            v = m[v];
            res.push_front(v);
        }
        return res;
    }

    std::string str() {
        std::string res = "{ ";
        for ( auto i = vertex_name.begin(); i != vertex_name.end() ; ++i ) {
            res += *i + " : { ";
            for( auto j = vertex_name.begin() ; j != vertex_name.end() ; ++j ) {
                if(edge[*i][*j] > 0) {
                  res += "(" + *j + ":" + std::to_string(edge[*i][*j]) + "), ";
                }
            }
            while(res.back() == ' ' || res.back() == ',') res.pop_back();
            res += " }, ";
        }
        while(res.back() == ' ' || res.back() == ',') res.pop_back();
        res += "}";
        return res;
    }
};

int main(int argc, char **argv) {
    UndirectedGraph graph;

	std::string vert = "";

	std::cout<<"Enter vertices (0 to stop):"<<std::endl;
	do{
		std::cin>>vert;
		graph.addVertex(vert);
	}while(vert != "0");

	std::string v1, v2; int w;
	std::cout<<std::endl<<"Enter edges [vert1 vert2 weight] (0 0 0 to stop):"<<std::endl;
	do{
		std::cin>>v1>>v2>>w;
		graph.addEdge(v1,v2,w);
	}while(v1 != "0" && v2 != "0" && w != 0);

	std::cout<<std::endl;

    std::cout<<"The Graph is: "<<graph.str()<<std::endl;

	std::cout<<"Enter the source and destination [v1 v2]:"<<std::endl;
	std::cin>>v1>>v2;

    std::cout<<"The BFS path is: ";
    std::string path = "";
    int cost;
    std::list<std::string> res = graph.bfs(v1,v2,cost);
    for(std::list<std::string>::iterator it = res.begin() ; it != res.end() ; ++it) {
        std::cout<<*it<<" ";
    }
    std::cout<<std::endl;
    std::cout<<"The cost is: "<<cost<<std::endl;
    return 0;
}