Мне нечего было делать дома, поэтому я сделал эту программу для вас. Он использует структуру данных TreeNode. Структура данных TreeNode позволяет иметь «неограниченное» количество подкатегорий/продуктов. Его также легко обойти, установив узел menu в его родительский или выбранный дочерний элемент. Вам нужно добавить/изменить продукты в метод Populate() и, возможно, изменить свойства MenuItem по вашему выбору (т.е. Price из Product относится к типу int).
using System;
using System.Linq;
using System.Collections.Generic;
using System.Collections.ObjectModel;
public class Program
{
private static List<Product> _cart = new List<Product>();
static void Main()
{
var menu = Populate();
Run(menu);
}
private static void ClickToContinue(string message)
{
Console.WriteLine($"{message}");
Console.ReadLine();
}
private static void ShowCart()
{
Console.WriteLine($"Your cart:");
for (int i = 0; i < _cart.Count; i++)
{
Console.WriteLine(String.Format("{0,-4} | {1,-15} | {2,5}", (i + 1).ToString(), _cart[i].Name, _cart[i].Price));
}
Console.WriteLine(String.Format("{0,-4} | {1,-15} | {2,5}", "Tot:", $"{_cart.Count()} items", _cart.Sum(item => item.Price).ToString()));
}
private static void PrintMenu(TreeNode<MenuItem> menu, string title)
{
title = string.IsNullOrEmpty(title) ? string.Empty : $"> {title.Trim()}";
var menuTitle = $"{menu.Value.Id}. {menu.Value.Name}".Trim();
if (menu.Parent == null)
{
Console.WriteLine($"{menuTitle} {title}\n");
return;
}
PrintMenu(menu.Parent, $"{menuTitle} {title}");
}
private static void Run(TreeNode<MenuItem> menu)
{
while (true)
{
Console.Clear();
PrintMenu(menu, string.Empty);
var selectedItem = SelectMenuItem(menu);
switch (selectedItem.Value)
{
case Category _:
menu = selectedItem;
break;
case Product p:
Console.WriteLine($"\nYou added {p.Name} to the cart.\n");
_cart.Add(p);
if (selectedItem.Parent != null)
menu = selectedItem.Parent;
ClickToContinue("\n\nPress any key to continue");
break;
case Cart _:
Console.WriteLine();
ShowCart();
if (selectedItem.Parent != null)
menu = selectedItem.Parent;
ClickToContinue("\n\nPress any key to continue");
break;
case GoBack b:
Console.WriteLine();
if (b.IsExit)
{
ShowCart();
ClickToContinue("\n\nGoodbye!\n\nPress any key to continue");
return;
}
menu = (selectedItem.Parent?.Parent != null) ? selectedItem.Parent.Parent : selectedItem.Parent;
break;
default:
throw new Exception($"{selectedItem.Value} not implemented");
case null:
throw new ArgumentNullException(nameof(selectedItem.Value));
}
}
}
private static TreeNode<MenuItem> SelectMenuItem(TreeNode<MenuItem> menuItem)
{
var minValue = menuItem.Children.OrderBy(i => i.Value.Id).FirstOrDefault().Value.Id;
var maxValue = menuItem.Children.OrderBy(i => i.Value.Id).LastOrDefault().Value.Id;
Console.WriteLine($"Please select an option between {minValue} and {maxValue}: ");
foreach (var child in menuItem.Children)
{
var price = child.Value is Product ? $"{(child.Value as Product).Price}" : string.Empty;
Console.WriteLine(String.Format("{0,-4} | {1,-15} | {2,5}", child.Value.Id.ToString(), child.Value.Name, price));
}
var selectedId = TryParseInput();
while (true)
{
var selectedItem = menuItem.Children.FirstOrDefault(m => m.Value.Id == selectedId);
if (selectedItem != null)
{
return selectedItem;
}
//Selected id does not exist in the menu
Console.WriteLine($"Please choose from one of the options.");
selectedId = TryParseInput();
}
}
private static TreeNode<MenuItem> Populate()
{
var menu = new TreeNode<MenuItem>(new Category(1, "Menu"));
var sweets = new TreeNode<MenuItem>(new Category(1, "Sweets"));
sweets.AddChildren(new List<MenuItem> {
new Product(1, "Chocolate R10", 15),
new Product(2, "Winegums R12", 20),
new Product(3, "Astros R15", 11),
new GoBack(9, "Back"),
});
var meats = new TreeNode<MenuItem>(new Category(2, "Meats"));
meats.AddChildren(new List<MenuItem> {
new Product(1, "Chicken", 13),
new Product(2, "Beef", 14),
new Product(3, "Seafood", 17),
new GoBack(9, "Back"),
});
var produce = new TreeNode<MenuItem>(new Category(3, "Produce"));
produce.AddChildren(new List<MenuItem> {
new Product(1, "Apple", 17),
new Product(2, "Tomato", 25),
new Product(3, "Orange", 24),
new GoBack(9, "Back"),
});
var cart = new TreeNode<MenuItem>(new Cart(4, "Cart"));
var exit = new TreeNode<MenuItem>(new GoBack(5, "Exit", true));
menu.AddChildren(new List<TreeNode<MenuItem>> {
sweets,
meats,
produce,
cart,
exit,
});
return menu;
}
private static int TryParseInput()
{
int returnInt;
while (!int.TryParse(Console.ReadLine(), out returnInt))
{
//Cannot parse input as an integer
Console.WriteLine($"Selection is not a number. Please try again.");
}
return returnInt;
}
}
public abstract class MenuItem
{
public MenuItem(int id, string name)
{
Id = id;
Name = name;
}
public int Id { get; private set; }
public string Name { get; private set; }
}
public class GoBack : MenuItem
{
public GoBack(int id, string name, bool isExit = false) : base(id, name)
{
IsExit = isExit;
}
public bool IsExit { get; set; }
}
public class Cart : MenuItem
{
public Cart(int id, string name) : base(id, name) { }
}
public class Category : MenuItem
{
public Category(int id, string name) : base(id, name) { }
}
public class Product : MenuItem
{
public Product(int id, string name, int price) : base(id, name)
{
Price = price;
}
public int Price { get; private set; }
}
public class TreeNode<T>
{
private readonly T _value;
private readonly List<TreeNode<T>> _children = new List<TreeNode<T>>();
public TreeNode(T value)
{
_value = value;
}
public TreeNode<T> this[int i] => _children[i];
public TreeNode<T> Parent { get; private set; }
public T Value { get { return _value; } }
public ReadOnlyCollection<TreeNode<T>> Children
{
get { return _children.AsReadOnly(); }
}
public TreeNode<T> AddChild(T value)
{
var node = new TreeNode<T>(value) { Parent = this };
_children.Add(node);
return node;
}
public TreeNode<T> AddChild(TreeNode<T> node)
{
node.Parent = this;
_children.Add(node);
return node;
}
public ReadOnlyCollection<TreeNode<T>> AddChildren(List<T> nodes)
{
foreach (var node in nodes)
{
AddChild(node);
}
return Children;
}
public ReadOnlyCollection<TreeNode<T>> AddChildren(List<TreeNode<T>> nodes)
{
foreach (var node in nodes)
{
AddChild(node);
}
return Children;
}
}
Выход:
1. Menu
Please select an option between 1 and 5:
1 | Sweets |
2 | Meats |
3 | Produce |
4 | Cart |
5 | Exit |
4
Your cart:
1 | Apple | 17
2 | Orange | 24
3 | Apple | 17
4 | Astros R15 | 11
Tot: | 4 items | 69
Press any key to continue
05.01.2020
