Linked List класс

//List.h
#pragma once
#ifndef LIST_H
#define LIST_H
 
#include <iostream>
#include <string>
 
using namespace std;
 
struct Node
{
    string _productName;
    double _price;
    string _description;
    Node* _next;
};
 
struct Product
{
    Node* _first;
    Node* _products;
};
 
class Inventory
{
public:
 
    Inventory();
    ~Inventory();
 
    void allocateNewMemoryforProduct(Product* product, Node p);
    void addProduct();
    void inInventory(Product* product);
    void searchProduct(Product* product);
    void sortProducts(Product* product);
    void removeProduct(Product* product);
    void displayAverageprice(Product* product);
    void displayProduct(Product* product);
    bool isEmpty(Product* product);
    void deleteProduct(Product* product);
};
 
#endif
 
//List.cpp
#include "List.h"
 
using namespace std;
 
Product product;
 
Inventory::Inventory()
{
 
}
 
Inventory::~Inventory()
{
    
}
 
void Inventory::inInventory(Product* product)
{
    product->_first = NULL;
}
 
void Inventory::allocateNewMemoryforProduct(Product* product, Node p)
{
    product->_products = new Node;
    product->_products->_productName = p._productName;
    product->_products->_price = p._price;
    product->_products->_description = p._description;
 
    product->_products->_next = NULL;
 
    if (product->_first == NULL)
    {
        product->_first = product->_products;
    }
    else
    {
        Node* temp = product->_first;
        while (temp->_next != NULL)
        {
            temp = temp->_next;
        }
        temp->_next = product->_products;
    }
}
 
void Inventory::addProduct()
{
    while (true)
    {
        Node p;
        
        cin.ignore();
        cout << "Enter name of product (to exit press '0'): ";
        getline(cin, p._productName);
        if (p._productName == "0")break;
        cout << "Enter price of product: ";
        cin >> p._price;
        cin.ignore();
        cout << "Enter description of product: ";
        getline(cin, p._description);
 
        allocateNewMemoryforProduct(&product, p);
    }
}
 
void Inventory::searchProduct(Product* product)
{
    Node* curr = product->_first;
    Node* search = NULL;
    string name;
    cout << "Enter name of product: ";
    getline(cin, name);
 
    while (curr != NULL && curr->_productName != name)
    {
        curr = curr->_next;
    }
 
    if (curr != NULL)
    {
        search = curr;
        curr = curr->_next;
        cout << "Product is found\n";
 
        cout << "Product " << search->_productName << endl;
        cout << "Price " << search->_price << '$' << endl;
        cout << "Description " << search->_description << endl;
    }
    else
    {
        cout << "Product was not found\n";
    }
}
 
void Inventory::sortProducts(Product* product)
{
    Node* temp = product->_first;
    while (temp != NULL)
    {
        Node* temp2 = temp;
        while (temp2 != NULL)
        {
            if (temp->_price > temp2->_price)
            {
                double temp3;
                temp3 = temp->_price;
                temp->_price = temp2->_price;
                temp2->_price = temp3;
                swap(temp->_productName, temp2->_productName);
                swap(temp->_description, temp2->_description);
            }
            temp2 = temp2->_next;
        }
        temp = temp->_next;
    }
    cout << "Products has been sorted\n";
}
 
void Inventory::removeProduct(Product* product)
{
    string name;
    if (product->_first == NULL)
    {
        cout << "The list is empty\n";
    }
    else
    {
        cin.ignore();
        cout << "Enter name of product: ";
        getline(cin, name);
        Node* curr = product->_first;
        Node* temp = NULL;
        while (curr != NULL)
        {
            if (curr->_productName == name)
            {
                break;
            }
            else
            {
                temp = curr;
                curr = curr->_next;
            }
        }
        if (curr == NULL)
        {
            cout << "Product " << name << " was not found\n";
        }
        else
        {
            if (product->_first != NULL)
            {
                product->_first = product->_first->_next;
            }
            else
            {
                temp->_next = curr->_next;
            }
            delete curr;
            cout << "Product " << name << " was deleted\n";
        }
    }
}
 
void Inventory::displayAverageprice(Product* product)
{
    double count = 0.0;
    double sum = 0.0;
    Node* temp = product->_first;
    while (temp != NULL)
    {
        sum += temp->_price;
        temp = temp->_next;
        count++;
    }
    cout << endl;
    if (sum > 0.0)
    {
        cout << "The average price of " << count << " products is:  " << (sum / count) << '$' << endl;
    }
    else
    {
        cout << "There are no product prices to display\n";
    }
}
 
void Inventory::displayProduct(Product* product)
{
    int count = 0;
    Node* curr = product->_first;
    while (curr != NULL)
    {
        cout << endl;
        cout << "Product " << (count + 1) << ": " << curr->_productName << endl;
        cout << "Price: " << curr->_price << '$' << endl;
        cout << "Description: " << curr->_description << endl;
        curr = curr->_next;
        count++;
    }
}
 
bool Inventory::isEmpty(Product* product)
{
    if (product->_first == NULL)
    {
        cout << "There are no products in the list\n";
        return false;
    }
    else
    {
        sortProducts(product);
        return true;
    }
}
 
void Inventory::deleteProduct(Product* product)
{
    while (product->_first != NULL)
    {
        product->_products = product->_first;
        product->_first = product->_first->_next;
        delete product->_products;
    }
}
 
//Main.cpp
#include <iostream>
#include "List.h"
 
using namespace std;
 
int main()
{
        Inventory Nick;
        Product product;
 
        cout << " ----------------- Welcome to NT shop! -----------------\n\n";
 
        cout << "To add new product press  *1*\n";
        cout << "To sort products press  *2*\n";
        cout << "To display products press  *3*\n";
        cout << "To display average of product prices press  *4*\n";
        cout << "To search product press  *5*\n";
        cout << "To remove product press  *6*\n";
        cout << "Go to main menu  *7*\n\n";
        cout << "To exit press '0'\n";
 
        int choice = 0;
 
        while (true)
        {
            cin >> choice;
            switch (choice)
            {
            case 1: Nick.addProduct();
                break;
            case 2: Nick.isEmpty(&product);
                break;
            case 3: Nick.displayProduct(&product);
                break;
            case 4: Nick.displayAverageprice(&product);
                break;
            case 5: Nick.searchProduct(&product);
                break;
            case 6: Nick.removeProduct(&product);
                break;
            case 7: cout << "To add new product press  *1*\n";
                cout << "To sort products press  *2*\n";
                cout << "To display products press  *3*\n";
                cout << "To display average of product prices press  *4*\n";
                cout << "To search product press  *5*\n";
                cout << "To remove product press  *6*\n";
                break;
            default: cout << "Goodbye!\n====== We hope to see you again soon! =) ======\n";
                cin.ignore();
                cin.get();
                return 0;
            }
            cout << endl;
            cout << "Go to main menu  *7* (press '0' to exit)\n";
        }
 
        Nick.~Inventory();
 
    cin.get();
    return 0;
}

// Products.h
 
#pragma once
#ifndef PRODUCTS_H
#define PRODUCTS_H
 
#include <iostream>
#include <string>
 
using namespace std;
 
struct Node
{
    string productName;
    double price;
    string description;
 
    Node* next;
};
 
class Inventory
{
    Node* _first;
    Node* _products;
 
public:
 
    Inventory();
    ~Inventory();
 
    void displayProducts(Inventory* product);
    void allocateNewMemoryforProduct(Inventory* product, Node p);
    void addProduct(Inventory* product);
    void sortProducts(Inventory* product);
    void averageofPrice(Inventory* product);
    void deleteElements(Inventory* product);
    void searchElement(Inventory* product);
    bool isEmpty(Inventory* product);
};
 
#endif
 
// Products.cpp
 
#include "Products.h"
 
using namespace std;
 
Inventory::Inventory()
{
    _first = NULL;
}
 
void Inventory::allocateNewMemoryforProduct(Inventory* product, Node p)
{
    product->_products = new Node;
    product->_products->productName = p.productName;
    product->_products->price = p.price;
    product->_products->description = p.description;
 
    product->_products->next = NULL;
    if (product->_first == NULL)
    {
        product->_first = product->_products;
    }
    else
    {
        Node* temp = product->_first;
        while (temp->next != NULL)
        {
            temp = temp->next;
        }
        temp->next = product->_products;
    }
}
 
void Inventory::addProduct(Inventory* product)
{
    while (true)
    {
        Node p;
 
        cin.ignore();
        cout << "Enter name of product (to exit press '0'): ";
        getline(cin, p.productName);
        if (p.productName == "0")break;
        cout << "Enter price of product: ";
        cin >> p.price;
        cin.ignore();
        cout << "Enter description of product: ";
        getline(cin, p.description);
 
        allocateNewMemoryforProduct(product, p);
    }
}
 
void Inventory::displayProducts(Inventory* product)
{
    if (product->_first == NULL)
    {
        cout << "There are no products in the list\n";
    }
    Node* curr = product->_first;
    int productsCount = 0;
    while (curr != NULL)
    {
        cout << endl;
        cout << "Product " << (productsCount + 1) << ": " << curr->productName << endl;
        cout << "Price: " << curr->price << '$' << endl;
        cout << "Description: " << curr->description << endl;
        curr = curr->next;
        productsCount++;
    }
}
 
void Inventory::sortProducts(Inventory* product)
{
    Node* temp = product->_first;
    while (temp != NULL)
    {
        Node* temp2 = temp;
        while (temp2 != NULL)
        {
            if (temp->price > temp2->price)
            {
                swap(temp->price, temp2->price);
                swap(temp->productName, temp2->productName);
                swap(temp->description, temp2->description);
            }
 
            temp2 = temp2->next;
        }
 
        temp = temp->next;
    }
    cout << "Products has been sorted\n";
}
 
void Inventory::averageofPrice(Inventory* product)
{
    double sum = 0.0;
    double count = 0.0;
 
    Node* p = product->_first;
    while (p != NULL)
    {
        sum += p->price;
        p = p->next;
        count++;
    }
    cout << endl;
    if (sum > 0.0)
    {
        cout << "The average price of " << count << " products is:  " << (sum / count) << '$' << endl;
    }
    else
    {
        cout << "There are no product prices to display\n";
    }
}
 
void Inventory::deleteElements(Inventory* product)
{
    string name;
    if (product->_first == NULL)
    {
        cout << "There are no products in the list\n";
    }
    else
    {
        cin.ignore();
        cout << "Enter name of product: ";
        getline(cin, name);
        Node* curr = product->_first;
        Node* temp = NULL;
        while (curr != NULL)
        {
            if (curr->productName == name)
            {
                break;
            }
            else
            {
                temp = curr;
                curr = curr->next;
            }
        }
        // Если продукт с нужным именем не был найден
        if (curr == NULL)
        {
            cout << "Product " << name << " not found\n";
        }
        else
        {
            if (product->_first == curr)
            {
                product->_first = product->_first->next;
            }
 
            else
            {
                temp->next = curr->next;
            }
            delete curr;
            cout << "Product " << name << " was deleted\n";
        }
    }
}
 
void Inventory::searchElement(Inventory* product)
{
    Node* curr = product->_first;
 
    Node* search = NULL;
    string name;
    cin.ignore();
    cout << "Enter name of product: ";
    getline(cin, name);
    while (curr != NULL && curr->productName != name)
    {
        curr = curr->next;
    }
    if (curr != NULL)
    {
        search = curr;
        curr = curr->next;
        cout << "Product is found\n";
        cout << endl;
        cout << "Product: " << search->productName << endl;
        cout << "Price: " << search->price << '$' << endl;
        cout << "Description: " << search->description << endl;
 
    }
    else
    {
        cout << "Product does not found\n";
    }
}
 
bool Inventory::isEmpty(Inventory* product)
{
    if (product->_first == NULL)
    {
        cout << "There are no products in the list\n";
        return false;
    }
    else
    {
        sortProducts(product);
        return true;
    }
}
 
Inventory::~Inventory()
{
    Node* temp = _first;
    Node* temp2 = _first;
    while (temp2)
    {
        temp = temp2;
        temp2 = temp->next;
        if (temp2) delete temp;
    }
}
 
// Main
 
#include <iostream>
#include "Products.h"
 
using namespace std;
 
int main()
{
    
        cout << " ----------------- Welcome to NT shop! -----------------\n\n";
 
        cout << "To add new product press  *1*\n";
        cout << "To sort products press  *2*\n";
        cout << "To display products press  *3*\n";
        cout << "To display average of product prices press  *4*\n";
        cout << "To search product press  *5*\n";
        cout << "To remove product press  *6*\n";
        cout << "Go to main menu  *7*\n\n";
        cout << "To exit press '0'\n";
 
        int choice = 0;
        Inventory inventory;
 
        while (true)
        {
            cin >> choice;
            switch (choice)
            {
            case 1: inventory.addProduct(&inventory);
                break;
            case 2: inventory.isEmpty(&inventory);
                break;
            case 3: inventory.displayProducts(&inventory);
                break;
            case 4: inventory.averageofPrice(&inventory);
                break;
            case 5: inventory.searchElement(&inventory);
                break;
            case 6: inventory.deleteElements(&inventory);
                break;
            case 7: cout << "To add new product press  *1*\n";
                cout << "To sort products press  *2*\n";
                cout << "To display products press  *3*\n";
                cout << "To display average of product prices press  *4*\n";
                cout << "To search product press  *5*\n";
                cout << "To remove product press  *6*\n";
                break;
            default: cout << "Goodbye!\n====== We hope to see you again soon! =) ======\n";
                cin.ignore();
                cin.get();
                return 0;
            }
            cout << endl;
            cout << "Go to main menu  *7* (press '0' to exit)\n";
        }
        
 
    cin.get();
    return 0;
}