init

SecureBank.Extensions/IEnumerableExtensions.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using static System.Runtime.InteropServices.JavaScript.JSType;
+
+namespace SecureBank.Extensions
+{
+    public static class IEnumerableExtensions
+    {
+        #region PUBLIC METHODS
+
+        public static IEnumerable<IEnumerable<T>> GetCombinations<T>(this IEnumerable<T> elements, int n)
+        {
+            if (elements.Count() < n)
+            {
+                throw new ArgumentException("Array length can't be less than number of selected elements");
+            }
+
+            if (n < 1)
+            {
+                throw new ArgumentException("Number of selected elements can't be less than 1");
+            }
+
+            if (elements.Count() == n)
+            {
+                return new List<IEnumerable<T>> { elements.ToList() };
+            }
+
+            List<List<T>> result = new List<List<T>>();
+
+            int[] indices = Enumerable.Range(0, n).ToArray();
+
+            while (indices[0] <= elements.Count() - n)
+            {
+                List<T> combination = new List<T>();
+
+                for (int i = 0; i < n; i++)
+                {
+                    combination.Add(elements.ElementAt(indices[i]));
+                }
+
+                result.Add(combination);
+
+                int j = n - 1;
+                while (j >= 0 && indices[j] == elements.Count() - n + j)
+                {
+                    j--;
+                }
+
+                if (j < 0)
+                {
+                    break;
+                }
+
+                indices[j]++;
+                for (int k = j + 1; k < n; k++)
+                {
+                    indices[k] = indices[k - 1] + 1;
+                }
+            }
+
+            return result;
+
+        }
+
+        #endregion
+
+
+
+        #region PRIVATE METHODS
+
+
+
+        #endregion
+    }
+}

SecureBank.Extensions/IListExtensions.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SecureBank.Extensions
+{
+    public static class IListExtensions
+    {
+        public static void Shuffle<T>(this IList<T> list)
+        {
+            Random rng = Random.Shared;
+            int n = list.Count;
+            while (n > 1)
+            {
+                n--;
+                int k = rng.Next(n + 1);
+                T value = list[k];
+                list[k] = list[n];
+                list[n] = value;
+            }
+        }
+    }
+}

SecureBank.Extensions/SecureBank.Extensions.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

SecureBank.Extensions/StringExtensions.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SecureBank.Extensions
+{
+    public static class StringExtensions
+    {
+        public static string CreateRandom(int length) => CreateRandom(length, "QWERTYUIOPASDFGHJKLZXCVBNMqwertyuiopasdfghjklzxcvbnm1234567890`~!@#$%^&*()-_=+[{]};:'\"\\|,<.>/?");
+        public static string CreateRandom(int length, IEnumerable<char> characters) => new string(Enumerable.Repeat(characters, length).Select(s => s.ElementAt(Random.Shared.Next(s.Count()))).ToArray());
+
+        public static string Shuffle(this string str)
+        {
+            char[] array = str.ToCharArray();
+            Random rng = Random.Shared;
+            int n = array.Length;
+            while (n > 1)
+            {
+                n--;
+                int k = rng.Next(n + 1);
+                char value = array[k];
+                array[k] = array[n];
+                array[n] = value;
+            }
+            return new string(array);
+        }
+    }
+}