CM-1038: Passing by Value vs Passing by Reference in C#

csharp-methods/PassingByValueVsPassingByReference/PassingByReferernceVsPassByValue.sln

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+Microsoft Visual Studio Solution File, Format Version 12.00
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+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "PassingByValueVsPassingByReference.Test", "PassingByValueVsPassingByReference.Test\PassingByValueVsPassingByReference.Test.csproj", "{7223F912-2689-44D6-8C1A-273E2A416474}"
+EndProject
+Global
+ GlobalSection(SolutionConfigurationPlatforms) = preSolution
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csharp-methods/PassingByValueVsPassingByReference/PassingByValueVsPassingByReference.Test/PassingByValueVsPassingByReference.Test.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+ <PropertyGroup>
+ <TargetFramework>net8.0</TargetFramework>
+ <ImplicitUsings>enable</ImplicitUsings>
+ <Nullable>enable</Nullable>
+
+ <IsPackable>false</IsPackable>
+ <IsTestProject>true</IsTestProject>
+ </PropertyGroup>
+
+ <ItemGroup>
+ <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0" />
+ <PackageReference Include="MSTest.TestAdapter" Version="3.0.4" />
+ <PackageReference Include="MSTest.TestFramework" Version="3.0.4" />
+ <PackageReference Include="coverlet.collector" Version="6.0.0" />
+ </ItemGroup>
+
+ <ItemGroup>
+ <ProjectReference Include="..\PassingByValueVsPassingByReference\PassingByValueVsPassingByReference.csproj" />
+ </ItemGroup>
+
+</Project>

csharp-methods/PassingByValueVsPassingByReference/PassingByValueVsPassingByReference.Test/PassingByValueVsPassingByReferenceUnitTest.cs

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+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace PassingByValueVsPassingByReference.Test
+{
+ [TestClass]
+ public class PassingByReferenceVsPassByValueUnitTest
+ {
+ [TestMethod]
+ public void GivenDoubleNumber_WhenPassedToUpdatePriceByPercentMethod_ThenNoChangeWillAffectTheNumber()
+ {
+ // Given
+ double number = 30;
+ int discountRate = 50;
+
+ // When
+ Program.UpdatePriceByPercent(number, discountRate);
+
+ //Assert
+ Assert.AreEqual(number, 30);
+ }
+
+ [TestMethod]
+ public void GivenDoubleNumber_WhenPassedToUpdatePriceByPercentByRefMethod_ThenWillChangeTheNumberValue()
+ {
+ // Given
+ double number = 30;
+ int discountRate = 50;
+
+ // When
+ Program.UpdatePriceByPercentByRef(ref number, discountRate);
+
+ //Assert
+ Assert.AreEqual(number, 15);
+ }
+
+ [TestMethod]
+ public void GivenProductObject_WhenPassedToApplyDiscountMethod_ThenWillChangeThePrice()
+ {
+ // Given
+ var product = new Product
+ {
+ ProductId = 1,
+ Price = 60,
+ Cost = 10
+ };
+
+ int discountRate = 50;
+
+ // When
+ Program.ApplyDiscount(product, discountRate);
+
+ //Assert
+ Assert.AreEqual(product.Price, 30);
+ }
+
+ [TestMethod]
+ public void GivenArrayOfDoubleNumbers_WhenPassedToUpdatePricesByPercentMethod_ThenWillChangeEveryItemInIt()
+ {
+ // Given
+ double[] originalPrices = [30, 15, 21.5, 50];
+ double[] prices = [.. originalPrices];
+
+ int discountRate = -50;
+
+ // When
+ Program.UpdatePricesByPercent(prices, discountRate);
+
+ //Assert
+ for (int i = 0; i < originalPrices.Length; i++)
+ {
+ Assert.AreEqual(prices[i], originalPrices[i] * (1 + discountRate / 100.0));
+ }
+ }
+
+ [TestMethod]
+ public void GivenAnUnassignedDoubleVariable_WhenPassedToMakeItZeroMethod_ThenWillHaveZero()
+ {
+ // Given
+ double zero;
+
+ // When
+ Program.MakeItZero(out zero);
+
+ //Assert
+ Assert.AreEqual(zero, 0);
+ }
+ }
+}

csharp-methods/PassingByValueVsPassingByReference/PassingByValueVsPassingByReference/PassingByValueVsPassingByReference.csproj

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

csharp-methods/PassingByValueVsPassingByReference/PassingByValueVsPassingByReference/Program.cs

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+namespace PassingByValueVsPassingByReference;
+
+public class Program
+{
+ public static void Main()
+ {
+ int discountRate = 50;
+ double productAPrice = 60;
+
+ double zero;
+
+ var product = new Product
+ {
+ ProductId = 1,
+ Price = 60,
+ Cost = 10
+ };
+
+ ApplyDiscount(product, 50);
+ Console.WriteLine($"{nameof(product)}: {product.Price}");
+
+ Console.WriteLine("Initial");
+ Console.WriteLine($"{nameof(productAPrice)}: {productAPrice}");
+
+ UpdatePriceByPercent(productAPrice, discountRate);
+ Console.WriteLine("After passing by value");
+ Console.WriteLine($"{nameof(productAPrice)}: {productAPrice}");
+
+ UpdatePriceByPercentByRef(ref productAPrice, discountRate);
+ Console.WriteLine("After passing by ref");
+ Console.WriteLine($"{nameof(productAPrice)}: {productAPrice}");
+
+ double productANewPrice = CalculateDiscount(productAPrice, discountRate);
+ Console.WriteLine($"{nameof(productANewPrice)}: {productANewPrice}");
+
+ double[] prices = [30, 15, 21.5, 50];
+ UpdatePricesByPercent(prices, -10);
+
+ MakeItZero(out zero);
+ Console.WriteLine($"{nameof(zero)}: {zero}");
+ }
+
+ public static void UpdatePricesByPercent(double[] prices, int rate)
+ {
+ for (int i = 0; i < prices.Length; i++)
+ {
+ prices[i] += prices[i] * rate / 100;
+ }
+ }
+
+ public static double CalculateDiscount(double price, int discountRate)
+ {
+ return price - price * discountRate / 100;
+ }
+
+ public static void UpdatePriceByPercent(double price, int discountRate)
+ {
+ price = price - price * discountRate / 100;
+ }
+
+ public static void UpdatePriceByPercentByRef(ref double price, int discountRate)
+ {
+ price -= price * discountRate / 100;
+ }
+
+ public static void ApplyDiscount(Product product, int discountRate)
+ {
+ product.Price -= product.Price * discountRate / 100;
+ }
+
+ public static void MakeItZero(out double price)
+ {
+ price = 0;
+ }
+}
+
+public class Product
+{
+ public int ProductId { get; set; }
+ public double Price { get; set; }
+ public double Cost { get; set; }
+}

csharp-methods/PassingByValueVsPassingByReference/README.md

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+## Passing By Value vs Passing By Reference in C#
+
+This repository contains the source code for the "Passing By Value vs Passing By Reference in C#" of articles on Code Maze
+