734 use decimal for money

exercises/bank-account/BankAccount.cs

@@ -12,15 +12,15 @@ public void Close()
         throw new NotImplementedException("You need to implement this function.");
     }
 
-    public float Balance
+    public decimal Balance
     {
         get
         {
             throw new NotImplementedException("You need to implement this property.");
         }
     }
 
-    public void UpdateBalance(float change)
+    public void UpdateBalance(decimal change)
     {
         throw new NotImplementedException("You need to implement this function.");
     }

exercises/bank-account/Example.cs

@@ -4,7 +4,7 @@ public class BankAccount
 {
     private readonly object _lock = new object();
 
-    private float balance;
+    private decimal balance;
     private bool isOpen;
 
     public void Open()
@@ -23,7 +23,7 @@ public void Close()
         }
     }
 
-    public float Balance
+    public decimal Balance
     {
         get
         {
@@ -39,7 +39,7 @@ public float Balance
         }
     }
 
-    public void UpdateBalance(float change)
+    public void UpdateBalance(decimal change)
     {
         lock(_lock)
         {

exercises/book-store/BookStore.cs

@@ -3,7 +3,7 @@
 
 public static class BookStore
 {
-    public static double Total(IEnumerable<int> books)
+    public static decimal Total(IEnumerable<int> books)
     {
         throw new NotImplementedException("You need to implement this function.");
     }

exercises/book-store/BookStoreTest.cs

@@ -9,104 +9,104 @@ public class BookStoreTest
     public void Only_a_single_book()
     {
         var basket = new[] { 1 };
-        Assert.Equal(8, BookStore.Total(basket));
+        Assert.Equal(8m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Two_of_the_same_book()
     {
         var basket = new[] { 2, 2 };
-        Assert.Equal(16, BookStore.Total(basket));
+        Assert.Equal(16m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Empty_basket()
     {
         var basket = Array.Empty<int>();
-        Assert.Equal(0, BookStore.Total(basket));
+        Assert.Equal(0m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Two_different_books()
     {
         var basket = new[] { 1, 2 };
-        Assert.Equal(15.2, BookStore.Total(basket));
+        Assert.Equal(15.2m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Three_different_books()
     {
         var basket = new[] { 1, 2, 3 };
-        Assert.Equal(21.6, BookStore.Total(basket));
+        Assert.Equal(21.6m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Four_different_books()
     {
         var basket = new[] { 1, 2, 3, 4 };
-        Assert.Equal(25.6, BookStore.Total(basket));
+        Assert.Equal(25.6m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Five_different_books()
     {
         var basket = new[] { 1, 2, 3, 4, 5 };
-        Assert.Equal(30, BookStore.Total(basket));
+        Assert.Equal(30m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Two_groups_of_four_is_cheaper_than_group_of_five_plus_group_of_three()
     {
         var basket = new[] { 1, 1, 2, 2, 3, 3, 4, 5 };
-        Assert.Equal(51.2, BookStore.Total(basket));
+        Assert.Equal(51.2m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Two_groups_of_four_is_cheaper_than_groups_of_five_and_three()
     {
         var basket = new[] { 1, 1, 2, 3, 4, 4, 5, 5 };
-        Assert.Equal(51.2, BookStore.Total(basket));
+        Assert.Equal(51.2m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Group_of_four_plus_group_of_two_is_cheaper_than_two_groups_of_three()
     {
         var basket = new[] { 1, 1, 2, 2, 3, 4 };
-        Assert.Equal(40.8, BookStore.Total(basket));
+        Assert.Equal(40.8m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Two_each_of_first_4_books_and_1_copy_each_of_rest()
     {
         var basket = new[] { 1, 1, 2, 2, 3, 3, 4, 4, 5 };
-        Assert.Equal(55.6, BookStore.Total(basket));
+        Assert.Equal(55.6m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Two_copies_of_each_book()
     {
         var basket = new[] { 1, 1, 2, 2, 3, 3, 4, 4, 5, 5 };
-        Assert.Equal(60, BookStore.Total(basket));
+        Assert.Equal(60m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Three_copies_of_first_book_and_2_each_of_remaining()
     {
         var basket = new[] { 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 1 };
-        Assert.Equal(68, BookStore.Total(basket));
+        Assert.Equal(68m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Three_each_of_first_2_books_and_2_each_of_remaining_books()
     {
         var basket = new[] { 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 1, 2 };
-        Assert.Equal(75.2, BookStore.Total(basket));
+        Assert.Equal(75.2m, BookStore.Total(basket));
     }
 
     [Fact(Skip = "Remove to run test")]
     public void Four_groups_of_four_are_cheaper_than_two_groups_each_of_five_and_three()
     {
         var basket = new[] { 1, 1, 2, 2, 3, 3, 4, 5, 1, 1, 2, 2, 3, 3, 4, 5 };
-        Assert.Equal(102.4, BookStore.Total(basket));
+        Assert.Equal(102.4m, BookStore.Total(basket));
     }
 }

exercises/book-store/Example.cs

@@ -4,17 +4,17 @@
 
 public static class BookStore
 {
-    private const double BookPrice = 8.0;
+    private const decimal BookPrice = 8.0m;
 
-    public static double Total(int[] books)
+    public static decimal Total(int[] books)
     {
         if (books.Length == 0)
-            return 0.0;
+            return 0.0m;
 
         var bookGroups = BookGroupsWithCount(books);
 
         return Enumerable.Range(1, bookGroups.Length)
-            .Min(size => CalculateTotalCost(bookGroups, size, 0.0));
+            .Min(size => CalculateTotalCost(bookGroups, size, 0.0m));
     }
 
     private static int[] BookGroupsWithCount(int[] books)
@@ -24,7 +24,7 @@ private static int[] BookGroupsWithCount(int[] books)
             .OrderByDescending(book => book)
             .ToArray();
 
-    private static double CalculateTotalCost(int[] bookGroups, int numberOfBooksToRemove, double totalCost)
+    private static decimal CalculateTotalCost(int[] bookGroups, int numberOfBooksToRemove, decimal totalCost)
     {
         var numberOfBooks = Math.Min(numberOfBooksToRemove, bookGroups.Length);
         if (numberOfBooks == 0)
@@ -48,23 +48,23 @@ private static int[] RemoveBooks(int[] bookGroups, int numberOfBooks)
 
     private static int RemoveBook(int books) => books - 1;
 
-    private static double BooksPrice(int differentBooks)
+    private static decimal BooksPrice(int differentBooks)
         => ApplyDiscount(RegularPrice(differentBooks), DiscountPercentage(differentBooks));
 
-    private static double RegularPrice(int books) => books * BookPrice;
+    private static decimal RegularPrice(int books) => books * BookPrice;
 
-    private static double DiscountPercentage(int differentBooks)
+    private static decimal DiscountPercentage(int differentBooks)
     {
         switch (differentBooks)
         {
-            case 5: return 25.0;
-            case 4: return 20.0;
-            case 3: return 10.0;
-            case 2: return 5.0;
-            default: return 0.0;
+            case 5: return 25.0m;
+            case 4: return 20.0m;
+            case 3: return 10.0m;
+            case 2: return 5.0m;
+            default: return 0.0m;
         }
     }
 
-    private static double ApplyDiscount(double price, double discountPercentage)
-        => Math.Round(price * (100.0f - discountPercentage) / 100.0f, 2);
+    private static decimal ApplyDiscount(decimal price, decimal discountPercentage)
+        => Math.Round(price * (100.0m - discountPercentage) / 100.0m, 2);
 }

exercises/ledger/Example.cs

@@ -5,7 +5,7 @@
 
 public class LedgerEntry
 {
-    public LedgerEntry(DateTime date, string description, float change)
+    public LedgerEntry(DateTime date, string description, decimal change)
     {
         Date = date;
         Description = description;
@@ -14,7 +14,7 @@ public LedgerEntry(DateTime date, string description, float change)
 
     public DateTime Date { get; }
     public string Description { get; }
-    public float Change { get; }
+    public decimal Change { get; }
 }
 
 public static class Ledger
@@ -27,7 +27,7 @@ public static LedgerEntry CreateEntry(string date, string description, int chang
 
     private static DateTime ParseDate(string date) => DateTime.Parse(date, System.Globalization.CultureInfo.InvariantCulture);
 
-    private static float ParseChange(int change) => change / 100.0f;
+    private static decimal ParseChange(int change) => change / 100.0m;
 
     private static CultureInfo CultureInfo(string locale)
     {
@@ -93,8 +93,8 @@ private static string FormatHeader(CultureInfo culture)
     private static string FormatDescription(string description) =>
         description.Length <= TruncateLength ? description : description.Substring(0, TruncateLength - TruncateSuffix.Length) + TruncateSuffix;
 
-    private static string FormatChange(IFormatProvider culture, float change) =>
-        change < 0.0 ? change.ToString("C", culture) : change.ToString("C", culture) + " ";
+    private static string FormatChange(IFormatProvider culture, decimal change) =>
+        change < 0.0m ? change.ToString("C", culture) : change.ToString("C", culture) + " ";
 
     private static string FormatEntry(IFormatProvider culture, LedgerEntry entry) =>
         string.Format("{0} | {1,-25} | {2,13}", FormatDate(culture, entry.Date), FormatDescription(entry.Description), FormatChange(culture, entry.Change));

exercises/ledger/Ledger.cs

@@ -5,7 +5,7 @@
 
 public class LedgerEntry
 {
-   public LedgerEntry(DateTime date, string desc, float chg)
+   public LedgerEntry(DateTime date, string desc, decimal chg)
    {
        Date = date;
        Desc = desc;
@@ -14,14 +14,14 @@ public LedgerEntry(DateTime date, string desc, float chg)
 
    public DateTime Date { get; }
    public string Desc { get; }
-   public float Chg { get; }
+   public decimal Chg { get; }
 }
 
 public static class Ledger
 {
    public static LedgerEntry CreateEntry(string date, string desc, int chng)
    {
-       return new LedgerEntry(DateTime.Parse(date, CultureInfo.InvariantCulture), desc, chng / 100.0f);
+       return new LedgerEntry(DateTime.Parse(date, CultureInfo.InvariantCulture), desc, chng / 100.0m);
    }
 
    private static CultureInfo CreateCulture(string cur, string loc)
@@ -113,9 +113,9 @@ private static string Description(string desc)
        return desc;
    }
 
-   private static string Change(IFormatProvider culture, float cgh)
+   private static string Change(IFormatProvider culture, decimal cgh)
    {
-       return cgh < 0.0 ? cgh.ToString("C", culture) : cgh.ToString("C", culture) + " ";
+       return cgh < 0.0m ? cgh.ToString("C", culture) : cgh.ToString("C", culture) + " ";
    }
 
    private static string PrintEntry(IFormatProvider culture, LedgerEntry entry)

generators/Exercises/Generators/BookStore.cs

@@ -12,7 +12,7 @@ protected override void UpdateTestMethod(TestMethod testMethod)
             if (testMethod.Input["basket"] is JArray)
                 testMethod.Input["basket"] = Array.Empty<int>();
 
-            testMethod.Expected = testMethod.Expected / 100.0f;
+            testMethod.Expected = testMethod.Expected / 100.0m;
             testMethod.InputParameters = new[] { "basket" };
             testMethod.UseVariablesForInput = true;
         }

generators/Output/Rendering/Render.cs

@@ -16,6 +16,7 @@ public string Object(object val)
             switch (val)
             {
                 case string str: return String(str);
+                case decimal dec: return Decimal(dec);
                 case double dbl: return Double(dbl);
                 case int i: return Int(i);
                 case uint ui: return Uint(ui);

generators/Output/Rendering/RenderNumber.cs

@@ -5,6 +5,8 @@ namespace Exercism.CSharp.Output.Rendering
 {
     public partial class Render
     {
+        public string Decimal(decimal dec) => $"{dec.ToString(CultureInfo.InvariantCulture)}m";
+
         public string Double(double dbl) => dbl.ToString(CultureInfo.InvariantCulture);
 
         public string Float(float flt) => flt.ToString(CultureInfo.InvariantCulture);