Class does not persist vector of objects after addition - c++

Question

My code is as shown below. The problem is inside the int main() function, r.printItems() is not printing anything. What am I missing here?
main.cpp
#include <bits/stdc++.h>
#include "Customer.h"
#include "MenuCreator.h"
#include "FoodItem.h"
MenuCreator m1;
void createCustomer() {
Customer c1("mrg", "m#gmail.com", "9654357", "+91");
}
void createRestaurantItem(Restaurant &rest) {
rest.addItems(FoodItem("t1"));
rest.addItems(FoodItem("D1"));
}
void createMenu() {
m1.createMenu("sg");
Category c1;
c1.setName("Non-veg");
m1.addCategory(c1);
Restaurant r1;
r1.setName("ABC");
r1.setDescription("Test Restaurant");
createRestaurantItem(r1);
c1.addRestaurants(r1);
}
vector<Restaurant> getRestaurantsForCategory(string category) {
return m1.getRestaurantsForCategories(category);
}
int main() {
createCustomer();
createMenu();
for (auto r: getRestaurantsForCategory("Non-veg")) {
r.printItems();
}
return 0;
}
MenuCreator.h
#include <bits/stdc++.h>
#include "Menu.h"
using namespace std;
class MenuCreator {
public:
void createMenu(string name) {
Menu m1;
m1.setName(name);
menu = m1;
}
void addCategory(const Category &categ) {
categories.push_back(categ);
}
const Menu &getMenu() const {
return menu;
}
const vector<Category> &getCategories() const {
return categories;
}
void addRestaurantForCategory(string name, const Restaurant restaurant) {
for(auto categ: categories) {
if (categ.getName() == name) {
categ.addRestaurants(restaurant);
}
}
}
const vector<Restaurant> &getRestaurantsForCategories(string category) {
for(auto categ: categories) {
if(categ.getName() == category) return categ.getRestaurants();
}
}
private:
Menu menu;
vector<Category> categories;
};
Menu.h
#include<bits/stdc++.h>
#include "Category.h"
using namespace std;
class Menu {
public:
const string &getName() const {
return name;
}
void setName(const string &name) {
Menu::name = name;
}
private:
string name;
string description;
vector<Category> categories;
};
Category.h
using namespace std;
class Category {
public:
const string &getName() const {
return name;
}
void setName(const string &name) {
Category::name = name;
}
const string &getDescription() const {
return description;
}
void setDescription(const string &description) {
Category::description = description;
}
const vector<Restaurant> &getRestaurants() const {
return restaurants;
}
void setRestaurants(const vector<Restaurant> &restaurants) {
Category::restaurants = restaurants;
}
void addRestaurants(const Restaurant &rt) {
Category::restaurants.push_back(rt);
}
private:
string name;
string description;
vector<Restaurant> restaurants;
};
FoodItem.h
#include <bits/stdc++.h>
#include <vector>
#include "FoodItem.h"
using namespace std;
class Restaurant {
public:
Restaurant() {
this->id = gen_random(12);
}
virtual ~Restaurant() {
}
const string &getName() const {
return name;
}
void setName(const string &name) {
Restaurant::name = name;
}
const string &getDescription() const {
return description;
}
void setDescription(const string &description) {
Restaurant::description = description;
}
double getLat() const {
return lat;
}
void setLat(double lat) {
Restaurant::lat = lat;
}
double getLang() const {
return lang;
}
void setLang(double lang) {
Restaurant::lang = lang;
}
const string &getImageUrl() const {
return imageUrl;
}
void setImageUrl(const string &imageUrl) {
Restaurant::imageUrl = imageUrl;
}
const string &getVideoUrl() const {
return videoUrl;
}
void setVideoUrl(const string &videoUrl) {
Restaurant::videoUrl = videoUrl;
}
const vector<FoodItem> &getItems() const {
return items;
}
void setItems(const vector<FoodItem> &items) {
Restaurant::items = items;
}
void addItems(const FoodItem &item) {
this->items.push_back(item);
}
string gen_random(const int len) {
string tmp_s;
static const char alphanum[] =
"0123456789"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz";
srand( (unsigned) time(NULL) * getpid());
tmp_s.reserve(len);
for (int i = 0; i < len; ++i)
tmp_s += alphanum[rand() % (sizeof(alphanum) - 1)];
return tmp_s;
}
const string &getId() const {
return id;
}
void printItems() {
for(auto it: items) {
cout<<"item: "<<it.getName()<<endl;
}
}
private:
string id;
string name;
string description;
double lat;
double lang;
string imageUrl;
string videoUrl;
string createdAt;
string updatedAt;
vector<FoodItem> items;
};
Restaurant.h
#include <bits/stdc++.h>
#include <vector>
#include "FoodItem.h"
using namespace std;
class Restaurant {
public:
Restaurant() {
this->id = gen_random(12);
}
virtual ~Restaurant() {
}
const string &getName() const {
return name;
}
void setName(const string &name) {
Restaurant::name = name;
}
const string &getDescription() const {
return description;
}
void setDescription(const string &description) {
Restaurant::description = description;
}
double getLat() const {
return lat;
}
void setLat(double lat) {
Restaurant::lat = lat;
}
double getLang() const {
return lang;
}
void setLang(double lang) {
Restaurant::lang = lang;
}
const string &getImageUrl() const {
return imageUrl;
}
void setImageUrl(const string &imageUrl) {
Restaurant::imageUrl = imageUrl;
}
const string &getVideoUrl() const {
return videoUrl;
}
void setVideoUrl(const string &videoUrl) {
Restaurant::videoUrl = videoUrl;
}
const vector<FoodItem> &getItems() const {
return items;
}
void setItems(const vector<FoodItem> &items) {
Restaurant::items = items;
}
void addItems(const FoodItem &item) {
this->items.push_back(item);
}
string gen_random(const int len) {
string tmp_s;
static const char alphanum[] =
"0123456789"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz";
srand( (unsigned) time(NULL) * getpid());
tmp_s.reserve(len);
for (int i = 0; i < len; ++i)
tmp_s += alphanum[rand() % (sizeof(alphanum) - 1)];
return tmp_s;
}
const string &getId() const {
return id;
}
void printItems() {
for(auto it: items) {
cout<<"item: "<<it.getName()<<endl;
}
}
private:
string id;
string name;
string description;
double lat;
double lang;
string imageUrl;
string videoUrl;
string createdAt;
string updatedAt;
vector<FoodItem> items;
};

Answer 1

When createMenu() in main.cpp is setting up the menu, it creates a local Category object named c1 and adds it to the menu, which makes a copy of c1 when pushingnit into the MenuCreator::categories vector. No Restaurant objects had been added to c1 yet when that copy is created. So when a Restaurant is then added to c1 afterwards, the copy is not updated. That is why there are no Restaurant objects in the menu when MenuCreator::getRestaurantsForCategory() tries to return them.
Change createMenu() to fully initialize c1 before adding it to the menu, eg:
void createMenu() {
m1.createMenu("sg");
Category c1;
c1.setName("Non-veg");
Restaurant r1;
r1.setName("ABC");
r1.setDescription("Test Restaurant");
createRestaurantItem(r1);
c1.addRestaurants(r1);
m1.addCategory(c1); // <-- move down here
}
Also, on a side note, the return value of MenuCreator::getRestaurantsForCategories() is undefined if the specified category is not found. Since the return value is a reference to a vector, it needs to either return a static vector that is empty, or else throw an exception.