How to implement coin jar in c# using Rest API?

Question

Hi Team I need some help with my requirement to implement coin jar in c# using rest api. My requirement are as below; "coin jar only accept latest us coinage, must have volume of 42 fluids ounces" "must have a counter to keep track of the total amount of money collected" "reset the count back to $0.00." My logic so far is as follows in c# using rest api using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; namespace CoinJarAPI.Controllers { public class CoinJarController : ApiController { // GET: api/CoinJar public IEnumerable string > Get() { return new string [] { "value1" , "value2" }; } // GET: api/CoinJar/5 public string Get( int id) { return "value" ; } // POST: api/CoinJar public void Post([FromBody] string value) { } // PUT: api/CoinJar/5 public void Put( int id, [FromBody] string value) { } // DELETE: api/CoinJar/5 public void Delete( int id) { } } } using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace CoinJarAPI.Interface { interface ICoinJar { void AddCoin(ICoin coin); decimal GetTotalAmount(); void Reset(); } public interface ICoin { decimal Amount { get ; set ; } decimal Volume { get ; set ; } } } using CoinJarAPI.Interface; using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace CoinJarAPI.Repository { public class Repository : ICoinJar { public void AddCoin(ICoin coin) { throw new NotImplementedException(); } public decimal GetTotalAmount() { throw new NotImplementedException(); } public void Reset() { throw new NotImplementedException(); } } }

Mario Scheeren · Answer

You should read about DEPENDENCY INJECTION!!! Startup.cs public class Startup { /* .... */ // This method gets called by the runtime. Use this method to add services to the container. // For more information on how to configure your application, visit https://go.microsoft.com/?LinkID=398940 public void ConfigureServices(IServiceCollection services) { services.AddControllersWithViews(); services.AddRazorPages(); // THIS IS IMPORTANT services.AddSingleton (provider => new CoinJar()); } /* .... */ Controller: [ApiController] [Route( "[controller]" )] public class MyControllerController : ControllerBase { private readonly ILogger logger; private readonly CoinJar coinJar; public MyControllerController (ILogger logger, CoinJar coinJar ) { this .logger = logger; this. coinJar = coinJar; } [HttpPost] public void AddCoin( [FromBody]eCoinType c oinType, [FromBody] int count = 1 ) { this.coinJar.AddCoin( c oinType, count); } [HttpGet] public decimal Amount() { return this.coinJar. GetTotalAmount(); } } Now get a clue how this wiorks?

Mario Scheeren · Answer

Add an Instance of your CoinJar to your services so you can add it using Dependency Injection. enum eCoinType { Cent = 1, Nickel = 5, Dime = 10, Quarter = 25, Half = 50, Large = 100 } class Coins { public readonly eCoinType CoinType; public int Amount { get ; set ; } = 0; public Coins(eCoinType coinType) { CoinType = coinType; } } class CoinJar { private readonly Coins[] coins = Enum.GetValues( typeof (eCoinvType)).Cast ().Select(x => new Coins(x)).ToArray(); public CoinJar() { } public void AddCoin(eCoinType coinType, int count = 1) { coins.First(x => x.CoinType == coinType).Amount += count; } public decimal GetTotalAmount() => coins.Select(c => ( decimal )c.CoinType * ( decimal )c.Amount).Sum() / 100m; public void Reset() { foreach (var c in coins) { c.Amount = 0; } } }

Guest User · Answer

Thanks so much for your help

Mario Scheeren · Answer

Hi, it was an example I added to one of my Blazor-Projects. so this "services.AddRazorsPages()" only applies to a Blazor-Project, bur still it shows how Dependency Injection works.

Guest User · Answer

Hi Mario Last question, on Startup.cs services.AddRazorsPages().// must this method should exist throughout the web-pages if you dont there is no need to be defined here or must?

Guest User · Answer

Hi Mario Where do i add this object? CoinJarController? How do i then expose Rest API endpoints of 1.add a coin 2.get the total amount 3.reset the coins Because when i want to ran it on the browser its not showing, need some bit of a help please on this one.