Im building a c++ program and i am recieving this error. I am also receiving 2 more errors for similar things.
I understand that this is normally due to not linking a library or something of that natrue, but im not currently using a library? atleast i dont think i am.
error LNK2019: unresolved external symbol "public: void__thiscall
Start::showMenu(void)"(?showMenu@start""QAEXXZ) referenced in function
"public: __thiscall Start:Start(void)" (??Start@@AE@XZ)
here is my error and code. Any help would be appreciated.
Start.cpp
#include "Start.h"
#include "Routes.h"
#include "std_lib_facilities.h"
using namespace std;
void bookNew();
void viewReceipts();
void showMenu();
Start::Start(void)
{
showMenu();
}
Start::~Start(void)
{
}
//Function Definitions
void showMenu(){
//output to the user
cout << "Welcome to the Flight Booking System\nPlease choose an action from the list below by typing the corresponding number.\n";
//array of choices that need to be output for the user
string top_level_options[] = {"[1]->View Receipts","[2]->Book new flight","[3]->Exit","Please input your choice:\n"};
//loops through choices and displays to the user
for each (string i in top_level_options) {
cout << i + "\n";
}
int input;
//reads the users input
cin >> input;
//does action based on the input from the user
switch (input-1) {
case 0 :
viewReceipts();
break;
case 1 :
bookNew();
break;
case 2 :
exit(1);
break;
default : cout << "You entered an invalid option. Please try again.";
showMenu();
break;
}
showMenu();
system("PAUSE");
}
void bookNew(){
//new instance of the Route class
cout << "You chose to book a new flight: \n";
Routes newJourney;
switch (newJourney.setStart()) {
case 1 :
showMenu();
break;
case 2 :
cout << "You have entered an invalid option. Please try again.";
newJourney.setStart();
break;
case 3 :
switch (newJourney.setDestination()) {
case 1 :
newJourney.setStart();
break;
case 2 :
cout << "You have entered an invalid option. Please try again.";
newJourney.setDestination();
break;
case 3 :
cout << "You have chosen to travel from";
break;
}
break;
}
}
void viewReceipts(){
cout << "You have chosen to view exisiting bookings.\nPlease choose a booking you would like to view by typing the correspoding number and hitting enter.\n";
}
start.h
#pragma once
class Start
{
public:
Start(void);
~Start(void);
void bookNew();
void viewReceipts();
void showMenu();
};
main.cpp
#include "std_lib_facilities.h"
#include "Routes.h"
#include "Start.h"
using namespace std;
//Function Declarations
//Main Function
int main()
{
Start menu;
return 0;
}
Routes
#include "Routes.h"
#include "std_lib_facilities.h"
#include "Start.h"
using namespace std;
vector<vector<string>> airports;
int startLocation;
int endLocation;
//function declarations
void readInput();
int setStart();
int setDestination();
void getDetails();
Routes::Routes(void)
{
//reads in the file and populates the arrays
readInput();
}
Routes::~Routes(void)
{
}
void readInput()
{
//opens the file
ifstream inFile;
inFile.open("data.txt");
//checks that the file reading in did not fail
if(inFile.fail()){
cerr << ("cant open data file.");
}
//variable to store the current word that is being analysed
//while the file isnt at the end
while(!inFile.eof()){
string currentWord;
//vector to store the routes
vector<string> currentStops;
//loops through every word in the file
while(inFile >> currentWord){
//if it reaches a ! ---end of the line
if(currentWord=="!"){
//adds the current vector to the airport vector
airports.push_back(currentStops);
//clears the current vector
currentStops.clear();
}else{
//adds the current word to the current vector
currentStops.push_back(currentWord);
}
}
}
}
int setStart()
{
cout << "Please select a start location from the list below by entering the corresponding number and hitting enter." << endl;
int endCounter = 0;
cout << "\n";
for(unsigned int i=0;i<airports.size();i++){
cout << "[" << i+1 << "] " << airports[i][0] << endl;
endCounter = i+1;
}
cout << "[" << endCounter << "] Go Back" << "\n";
int chosenIndex;
cin >> chosenIndex;
if(chosenIndex==endCounter){
cout << "You have chosen to go back.\n\n";
return 1;
}else{
if(chosenIndex>endCounter || chosenIndex<endCounter){
cout << "You have chosen an invalid option. Please try again.\n\n";
setStart();
return 2;
}else{
startLocation = chosenIndex-1;
return 3;
}
}
return 0;
}
int setDestination()
{
cout << "Please choose your desired destination: \n";
cout << "From " << airports[startLocation][0] << " to: \n";
int endCounter;
for(unsigned int i=1;i<airports[startLocation].size();i++){
cout << "[" << i << "] " << airports[startLocation][i] << endl;
endCounter = i+1;
}
cout << "[" << endCounter << "] Go Back" << "\n";
int chosenIndex;
cin >> chosenIndex;
if(chosenIndex==endCounter){
cout << "You chose to go back. \n\n";
return 1;
}else{
if(chosenIndex>endCounter){
cout << "You chose an invalid option. Please try again.";
return 2;
}else{
endLocation = chosenIndex -1;
return 3;
}
}
return 0;
}
void getDetails()
{
cout << "You have chosen to travel from " << airports[startLocation][0] << " to " << airports[startLocation][endLocation] << ".\n";
}
Routes.h
#pragma once
class Routes
{
public:
Routes(void);
~Routes(void);
int setStart();
int setDestination();
private:
};
You are declaring and defining the following at namespace scope in Start.cpp when you probably don't mean to:
void bookNew();
void viewReceipts();
void showMenu();
Your constructor is calling Start::showMenu(), which you actually did declare properly:
Start::Start(void) {
showMenu(); // this calls Start::showMenu(), which is not what you defined.
}
You need to get rid of the three declarations above and redefine the implementations as follows:
void Start::showMenu() {
//output to the user
cout << "Welcome to the Flight Booking System\n"
"Please choose an action from the list below "
"by typing the corresponding number.\n";
// ...
}
void Start::bookNew() { /* ... */ }
void Start::viewReceipts() { /* ... */ }
You may also have similar problems with Routes, which is using namespace-scope methods and global variables instead of class member equivalents.