Before anyone calls me out for not looking at pre-existing questions, I have looked and realise that it is to do with declaration, but I still can't get it to work (might be something to do with me using vectors).
Manager.h:
#include "Flight.h"
#ifndef manager_h
#define manager_h
class Manager {
static vector<Airport> airports;
static vector<Flight> flights;
public:
static void loadAirports();
static void loadFlights();
static Airport getAirport(string code);
static vector<string> split(const string &s, vector<string> &elems);
};
#endif
Manager.cpp:
#include "Manager.h"
void Manager::loadAirports ()
{
ifstream airportfile("airports.txt");
string line;
while (getline(airportfile, line))
{
vector<string> values;
split(line, values);
Airport airport (values[0], values[1], atoi(values[2].c_str()));
airports.push_back(airport);
}
}
void Manager::loadFlights ()
{
ifstream flightfile("flights.txt");
string line;
while (getline(flightfile, line))
{
vector<string> values;
split(line, values);
Flight flight (getAirport(values[0]), getAirport(values[1]), atoi(values[2].c_str()), atoi(values[3].c_str()));
flights.push_back(flight);
}
cout << flights.size() << endl;
}
Airport Manager::getAirport (string code)
{
for (int i = 1; i < (int)airports.size(); i++)
{
if (airports[i].code == code)
return airports[i];
}
throw exception();
}
vector<string> Manager::split(const string &s, vector<string> &elems) {
stringstream ss(s);
string item;
while(getline(ss, item, ',')) {
elems.push_back(item);
}
return elems;
}
It is throwing this error:
Manager.obj : error LNK2001: unresolved external symbol "private: static struct Vector Manager::airports" (?airports@Manager@@0U?$Vector@UAirport@@@@A)
Manager.obj : error LNK2001: unresolved external symbol "private: static struct Vector Manager::flights" (?flights@Manager@@0U?$Vector@UFlight@@@@A)
I realise i need to define the vectors, but how and where? I tried creating an empty constructor and then doing
Manager::Manager ()
{
vector<string> flights;
vector<string> airports;
}
But it just gave me a re-definition error.
You have to define them in the .cpp
file:
vector<string> Manager::flights;
vector<string> Manager::airports;
In your .cpp file, you need to add the definitions of the static variables:
vector<Airport> Manager::airports;
vector<Flight> Manager::flights;
See Why are classes with static data members getting linker errors? from the C++ FAQ.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With