Add addition without arithmetic algorithm

Algorithms.Tests/Numeric/AdditionWithoutArithmeticsTests.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Numerics;
+using Algorithms.Numeric;
+using NUnit.Framework;
+
+namespace Algorithms.Tests.Numeric;
+
+public static class AdditionWithoutArithmeticTests
+{
+    [TestCase(3, 5, 8)]
+    [TestCase(13, 5, 18)]
+    [TestCase(-7, 2, -5)]
+    [TestCase(0, -7, -7)]
+    [TestCase(-321, 0, -321)]
+    public static void CalculateAdditionWithoutArithmetic_Test(int first, int second, int expectedResult)
+    {
+        // Act
+        var result = AdditionWithoutArithmetic.CalculateAdditionWithoutArithmetic(first, second);
+
+        // Assert
+        Assert.That(result, Is.EqualTo(expectedResult));
+    }
+}

Algorithms/Numeric/AdditionWithoutArithmetic.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Numerics;
+
+namespace Algorithms.Numeric;
+
+/// <summary>
+///     Add the integers without arithmetic operation.
+/// </summary>
+public static class AdditionWithoutArithmetic
+{
+    /// <summary>
+    ///    Returns the sum of two integers.
+    /// </summary>
+    /// <param name="first">First number to add.</param>
+    /// <param name="second">Second number to add.</param>
+    /// <returns>Sum of the two numbers.</returns>
+    public static int CalculateAdditionWithoutArithmetic(int first, int second)
+    {
+        while (second != 0)
+        {
+            int c = first & second;      // Carry
+            first ^= second;             // Sum without carry
+            second = c << 1;            // Carry shifted left
+        }
+        return first;
+    }
+}

README.md

@@ -67,6 +67,7 @@ find more than one implementation for the same objective but using different alg
     * [Modular Multiplicative Inverse](./Algorithms/ModularArithmetic/ModularMultiplicativeInverse.cs)
   * [Numeric](./Algorithms/Numeric)
     * [Absolute](./Algorithms/Numeric/Abs.cs) 
+    * [Addition Without Arithmetic](./Algorithms/Numeric/AdditionWithoutArithmetic.cs) 
     * [Aliquot Sum Calculator](./Algorithms/Numeric/AliquotSumCalculator.cs)
     * [Amicable Numbers Checker](./Algorithms/Numeric/AmicableNumbersChecker.cs)
     * [Decomposition](./Algorithms/Numeric/Decomposition)