C++ Graph data Structure - c++

Question

I am writing a graph implementation in c++ where the cities are vertices, flights from one city to another city represent an edge, and the weights are the distances between those cities. The vertices,edges, and weights are stored in a file and when the program runs it would load the vertices, edges, and weights into the program. I am using an adjacency matrix where it represents the edges.
Now when the program runs it will prompt the user to either:
Choose Departure city
Exit. Option two just terminates the program.
If the user chooses option one, then it will list all the cities from the file. There a seven cities I chose. So it will look like 1.)Los Angeles 2.) New York 3.) Miami and so on until option 7. When the user chooses an option it will then list all the destination cities except the departure city the user chose. There would be three possibilities once the user chooses his destination city.
Now the first possibility would be there would be no direct or through connection between city A and city B and the program will output, No destination between [departure city] and [destination city] , press any key to return. Once the user presses any key, the menu will display again. The Second possibility would be if there is a direct connection between the city then the program would output the direct connection between [departure city]-[destination city] = [miles] and the miles between the city, or if there isn't a direct connection it will say no direct connection and the user can go back to the menu.
The third possibility would be that there would be a through connection and it will show the departure city and destination city with all the cities between them and the total miles it covers between them and the user can press any key to return to the menu.
Now the problem I"m having is getting the info from the file, I can't figure out how to get the info from the file or how to write the file so the program knows which are the vertices,edges,and weights. Also, how to display the cities and which have the direct connection, through connection, or no connection at all.
include <iostream>
#include <fstream>
#pragma once
const int NULL_EDGE = 0;
typedef std::string String;
class GraphType
{
private:
int edges[50][50];
int m_numVertices;
int m_maxVertices;
int m_distance;
String* m_vertices;
bool* marks; // marks[i] is the mark for vertices[i]
int IndexIs(String*, String);
public:
GraphType();
~GraphType();
bool isEmpty() const;
bool isFull(); //to do
int GetWeight(String, String); // to do
void ClearMarks(); // to do
void MarkVertex(String) // to do
bool isMarked(String) // to do
void addVertex(String);
void addEdge(String, String, int);
void displayCities();
};
#include "GraphType.h"
GraphType::GraphType()
{
m_maxVertices = 50;
m_distance = 0;
m_vertices = new String[m_maxVertices];
marks = new bool[50];
std::ifstream loadFile;
loadFile.open("load.txt");
if (loadFile.fail())
std::cout << " Error opening load.txt\n";
else
{
//stuck here
}
loadFile.close();
}
GraphType::~GraphType()
{
delete[] m_vertices;
delete[] marks;
}
int GraphType::IndexIs(String* vertices, String vertex)
{
int index = 0;
while (!(vertex == m_vertices[index]) == 0)
index++;
return index;
}
void GraphType::addVertex(String vertex)
{
m_vertices[m_numVertices] = vertex;
for (int i = 0; i < m_numVertices; i++)
{
edges[m_numVertices][i] = NULL_EDGE;
edges[i][m_numVertices] = NULL_EDGE;
}
m_numVertices++;
}
void GraphType::addEdge(String startVertex, String destVertex, int weight)
{
int row;
int col;
row = IndexIs(m_vertices, startVertex);
col = IndexIs(m_vertices, destVertex);
edges[row][col] = weight;
}
void GraphType::displayCities()
{
//stuck here
}
bool GraphType::isEmpty() const
{
return (m_numVertices == 0);
}
#include "GraphType.h"
int FlyMenu();
void CitiesMenu(GraphType&);
int main()
{
int choose;
GraphType gt;
do
{
choose = FlyMenu();
switch (choose)
{
case 1: CitiesMenu(gt);
break;
case 2:
break;
default: std::cout << " Invalid Input\n";
break;
}
} while (choose != 2);
return 0;
}
int FlyMenu()
{
int option;
std::cout << " 1.) Choose Depature City\n";
std::cout << " 2.) Exit\n";
std::cout << " Enter option: ";
std::cin >> option;
return option;
}
void CitiesMenu(GraphType& gt)
{
gt.displayCities();
}
I know about the depth Traversal and breadth Traversal algorithms to see if there is a connection between a city or not, but I don't know how to implement them for this scenario. I can't use the Standard Template Library, only std::vector. I was thinking about writing another class, but I don't know what what that class will help me with.

Answer 1

From what I got you have two questions:
read / write from file: the simplest solution would be freopen.
freopen("input","r",stdin)
freopen("output","w",stdout)
now every cin & cout operation will be done on the files you defined on freopen
implementing DFS / BFS: I will code the simplest type of DFS for you and you have to edit it to suite you program.
bool visit[MAX_CITY + 10];
void DFS(int x){
visit[x] = 1;
for (int i=1;i<=MAX_CITY;i++){
int nx = i;
if (adj[x][i] == -1) continue; // a cost of -1 means no flight
if (visit[nx]) continue;
DFS(nx);
}
}