Graph Implementation for Airline Flights in C++

This project requires the implementation of a graph data structure in C++ to represent airline flights between cities. The program loads city connections and distances from a 'load.txt' file. Users can select a departure and destination city, and the program will determine if there are direct or through connections, displaying the routes and distances. The program will output the shortest through connection if available. The project also requires a 'readme.txt' file documenting the chosen cities, connections, and distances.

program in C++ using GRAPHS
An airline company needs an abstract data structure to represent the available flights. The company's
IT department chose a graph. You must use a graph to write the program required by this
assignment.
Cities, Connections and Distances, and load.txt file
The vertices of the graph represent cites. The edges represented the connections between one city
and another. The weights represented the distance in miles between the two cites connected by an
edge.
You choose the cities and connections. Include enough cities and connections that I will be able to
meaningful test your program.
Make the distances between the cities realistic. You can use Google Maps and round off the distance.
These vertices, edges and weights should be stored in a text file named load.txt, which you will turn in
with your assignment. When your program starts, it will use the load.txt file to load the vertices, edges
and weights into your program.
Readme.txt file
Document in a readme.txt file (which you will turn in with your assignment) the cities and connections
you choose, and the distances assigned to each connection. When describing connections, separately
list direct connections from through connections.
A direct connection means you can fly from the departure city to the destination city without having to
first fly through another city. For this type of connection, you list the departure city, the destination
city, and the distance between the two cities.
A through connection means you can fly from the departure city to the destination city, but you first
have to first fly to at least one another city. For this type of connection, you list the departure city, the
destination city, each city between the departure city and the destination city which is part of the
connection, and the total distance between the departure city and the destination city.
Project Startup
As mentioned above, when your program starts, it will use the load.txt file to load the vertices, edges
and weights into your graph. The program then will display a menu, and prompt the user to enter a
choice:
1. Choose departure city
2. Exit
You may assume the user enters 1 or 2. No input validation is required.
If the user chooses 2. Exit, then the program ends.
Program lists Departure Cities, and user chooses
If the user choose 1. Choose departure city, then the program lists the cities. The cities don't have to
be listed in any particular order. However, an ascending letter or number should be to the left of each
city so the user can use that letter or number to choose a city. For example:

1. Chicago
2. Denver
3. Atlanta
(and so on)
Choose city:
or
A. Chicago
B. Denver
C. Atlanta
(and so on)
Choose city:
You may assume the user enters a valid number or letter; no input validation is required.
Program lists Destination Cities, and user chooses
Once a user chooses a city, then the program displays "Destination cites" followed by all of the cities
except the departure city. Again, the cities don't have to be listed in any particular order, but an
ascending letter or number should be to the left of each city so the user can use that letter or number
to choose a city.
You again may assume the user enters a valid number or letter; no input validation is required.
If no connection
Once the user chooses a destination city, if there is no direct or through connection between the
departure and destination cities, then the program will output:
No connection between [name of departure city] and [name of destination city]
Press any key to return to menu.
After the user presses the any key (we'll assume the user has an any key on their keyboard :-), then
the menu which displayed at the program startup (1. Choose departure city 2. Exit) will re-display and
the program will continue as stated above.
If connection, direct connection?
If there is some connection between the departure and destination cities ... the next issue is whether
there is a direct connection between the departure and destination cities.
If there is no direct connection between the departure and destination cities (in other words, only a
through connection), then the program will output:
No direction connection between [name of departure city] and [name of destination city]
Then the program will output the information in the next section (If connection, through connection?).
If there is a direct connection between the departure and destination cities (there presumably only
would be one), then the program will output:
Direct connection between [name of departure city] and [name of destination city]
Then the program will output the information in the next section (If connection, through connection?).

If connection, through connection?
If there is no through connection between the departure and destination cities (in other words, only a
direct connection), then the program will output:
No through connection between [name of departure city] and [name of destination city]
Press any key to return to menu [after which the menu displayed at program startup is re-displayed]
If there is at least one through connection between the departure and destination cities, then the
program will output all through connections (there may be more than one) in ascending order of
distance, listing the intermediate cities, as follows:
Through connection between [name of departure city] and [name of destination city] via [list name or
names of cities in between] - [number of miles] miles
After this listing, the program prompts the user to "Press any key to return to menu", after which the
menu displayed at program startup is re-displayed.