Program.cs

using System;
using System.Collections.Generic;
using System.IO;

namespace InventoryManagementSystem
{
    //Store amount and value
    public struct Stats
    {
        public int Count;
        public double Value;
        public Stats(int c, double v) { Count = c; Value = v; }
    }

    //Store product details
    public class Product
    {
        public string Name { get; set; }
        public double Price { get; set; }
        public int Quantity { get; set; }

        public Product(string n, double p, int q) { Name = n; Price = p; Quantity = q; }

        //Calculates value
        public double GetValue() => Price * Quantity;

        public void Show()
        {
            Console.WriteLine($"{Name} - ${Price:F2} x {Quantity} = ${GetValue():F2}");
        }
    }

    public class Inventory
    {
        private List<Product> items = new List<Product>();
        private const string FILE = "inventory.txt";

        //Adds product to inventory
        public void Add(Product p) { items.Add(p); Console.WriteLine($" Added {p.Name}"); }
        public bool Remove(string name)
        {
            //For loop until product is found
            for (int i = 0; i < items.Count; i++)
            {
                if (items[i].Name.ToLower() == name.ToLower())
                {
                    Console.WriteLine($" Removed {items[i].Name}");
                    items.RemoveAt(i);
                    return true;
                }
            }
            return false;
        }
        // Edits current product details
        public bool Edit(string name)
        {
            foreach (var p in items)
            {
                if (p.Name.ToLower() == name.ToLower())
                {
                    Console.WriteLine($"\nCurrent: {p.Name} - ${p.Price:F2} x {p.Quantity}");
                    Console.Write("New Price (press Enter to keep current): $");
                    string priceInput = Console.ReadLine();
                    if (!string.IsNullOrWhiteSpace(priceInput))
                        p.Price = double.Parse(priceInput);
                    
                    Console.Write("New Quantity (press Enter to keep current): ");
                    string qtyInput = Console.ReadLine();
                    if (!string.IsNullOrWhiteSpace(qtyInput))
                        p.Quantity = int.Parse(qtyInput);
                    
                    Console.WriteLine($" Updated {p.Name}");
                    return true;
                }
            }
            return false;
        }
        //Checks for products, then displays all inventory
        public void ShowAll()
        {
            Console.WriteLine("\n---- INVENTORY ----");
            if (items.Count == 0) { Console.WriteLine("Empty"); return; }
            foreach (var p in items) p.Show();
        }

        public Product Find(string name)
        {
            foreach (var p in items)
                if (p.Name.ToLower() == name.ToLower()) return p;
            return null;
        }

        public Stats GetStats()
        {
            double total = 0;
            foreach (var p in items) total += p.GetValue();
            return new Stats(items.Count, total);
        }

        //Save feature
        public void Save()
        {
            try
            {
                using (var w = new StreamWriter(FILE))
                    foreach (var p in items)
                        w.WriteLine($"{p.Name}|{p.Price}|{p.Quantity}");
                Console.WriteLine($" Saved {items.Count} items");
            }
            catch (Exception e) { Console.WriteLine($"Error: {e.Message}"); }
        }

        //Loads inventory for user
        public void Load()
        {
            if (!File.Exists(FILE)) return;
            try
            {
                items.Clear();
                foreach (var line in File.ReadAllLines(FILE))
                {
                    var parts = line.Split('|');
                    if (parts.Length == 3)
                        items.Add(new Product(parts[0], double.Parse(parts[1]), int.Parse(parts[2])));
                }
                Console.WriteLine($" Loaded {items.Count} items...");
            }
            catch (Exception e) { Console.WriteLine($"Error: {e.Message}"); }
        }
    }

    //Main UI
    class Program
    {
        static void Main()
        {
            Console.Clear();
            Console.WriteLine("\n----- INVENTORY MANAGEMENT SYSTEM -----\n");
            
            var inv = new Inventory();
            inv.Load();
            bool run = true;

            while (run)
            {
                Console.WriteLine("\n---- MAIN MENU ----\n");
                Console.WriteLine(" 1 | Add Product     ");
                Console.WriteLine(" 2 | Remove Product   ");
                Console.WriteLine(" 3 | Edit Product     ");
                Console.WriteLine(" 4 | Find Product     ");
                Console.WriteLine(" 5 | Show All         ");
                Console.WriteLine(" 6 | Statistics       ");
                Console.WriteLine(" 7 | Save & Exit      ");
                Console.Write("\n Choice: ");
                
                switch (Console.ReadLine())
                {
                    //Define each option
                    case "1":
                        Console.WriteLine("\n--- ADD PRODUCT ---");
                        Console.Write("Name: "); var n = Console.ReadLine();
                        Console.Write("Price: $"); var p = double.Parse(Console.ReadLine());
                        Console.Write("Quantity: "); var q = int.Parse(Console.ReadLine());
                        inv.Add(new Product(n, p, q));
                        break;
                    case "2":
                        Console.WriteLine("\n--- REMOVE PRODUCT ---");
                        Console.Write("Product Name: ");
                        if (!inv.Remove(Console.ReadLine()))
                            Console.WriteLine("Product not found");
                        break;
                    case "3":
                        Console.WriteLine("\n--- EDIT PRODUCT ---");
                        Console.Write("Product Name: ");
                        if (!inv.Edit(Console.ReadLine()))
                            Console.WriteLine("Product not found");
                        break;
                    case "4":
                        Console.WriteLine("\n--- FIND PRODUCT ---");
                        Console.Write("Name: ");
                        var found = inv.Find(Console.ReadLine());
                        if (found != null) { Console.WriteLine(); found.Show(); }
                        else Console.WriteLine("Not found, try again");
                        break;
                    case "5":
                        inv.ShowAll();
                        break;
                    case "6":
                        var s = inv.GetStats();
                        Console.WriteLine("\n ----STATISTICS---- \n");
                        Console.WriteLine($" Total Items:  {s.Count,-14}");
                        Console.WriteLine($" Total Value:  ${s.Value,-13:F2}");
                        break;
                    case "7":
                        inv.Save();
                        Console.WriteLine("\nThank you! Goodbye!");
                        run = false;
                        break;
                    default:
                        Console.WriteLine("Invalid choice. Try again.");
                        break;
                }
            }
        }
    }
}