C# Tutorial 4
In this part of my C# tutorial we’ll cover methods in detail. We’ll cover Pass by Value versus Pass by Reference, Out Parameter, Params, Named Parameters, Method Overloading, Enum and much more.
All of the code and a transcript of the video follows the video below.For best results take notes on the cheat sheet provided.
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Code & Cheat Sheet
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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace CSharpTutA.cs { class Program { static void Main(string[] args) { // ----- PASSING BY VALUE ----- double x = 5; double y = 4; Console.WriteLine("5 + 4 = {0}", GetSum(x, y)); // Even though the value for x changed in // method it remains unchanged here Console.WriteLine("x = {0}", x); // ----- OUT PARAMETER ----- // You can pass a variable as an output // variable even without assigning a // value to it int solution; // A parameter passed with out has its // value assigned in the method DoubleIt(15, out solution); Console.WriteLine("15 * 2 = {0}", solution); // ----- PASS BY REFERENCE ----- int num1 = 10; int num2 = 20; Console.WriteLine("Before Swap num1 : {0} num2 : {1}", num1, num2); Swap(ref num1, ref num2); Console.WriteLine("After Swap num1 : {0} num2 : {1}", num1, num2); // ----- PARAMS ----- // You are able to pass a variable amount // of data of the same data type into a // method using params. You can also pass // in an array. Console.WriteLine("1 + 2 + 3 = {0}", GetSumMore(1, 2, 3)); // ----- NAMED PARAMETERS ----- // You can pass values in any order if // you used named parameters PrintInfo(zipCode: 15147, name: "Derek Banas"); // ----- METHOD OVERLOADING ----- // You can define methods with the same // name that will be called depending on // what data is sent automatically Console.WriteLine("5.0 + 4.0 = {0}", GetSum(5.0, 4.5)); Console.WriteLine("5 + 4 = {0}", GetSum(5, 4)); Console.WriteLine("5 + 4 = {0}", GetSum("5", "4")); // ----- ENUM ----- CarColor car1 = CarColor.Blue; PaintCar(car1); Console.ReadLine(); } // ----- PASS BY VALUE ----- // By default values are passed into a method // and not a reference to the variable passed // Changes made to those values do not effect the // variables outside of the method // If you assign a value then it is optional to // pass static double GetSum(double x = 1, double y = 1) { double temp = x; x = y; y = temp; return x + y; } // ----- OUT PARAMETER ----- // A parameter marked with out must be assigned // a value in the method static void DoubleIt(int x, out int solution) { solution = x * 2; } // ----- PASS BY REFERENCE ----- // If a variable is passed by reference changes // to its value in the method effect it outside // of the method public static void Swap(ref int num1, ref int num2) { int temp = num1; num1 = num2; num2 = temp; } // ----- PARAMS ----- // The params array must be the last parameter // in the list static double GetSumMore(params double[] nums) { double sum = 0; foreach (int i in nums) { sum += i; } return sum; } // ----- NAMED PARAMETERS ----- static void PrintInfo(string name, int zipCode) { Console.WriteLine("{0} lives in the zip code {1}", name, zipCode); } // ----- METHOD OVERLOADING ----- static double GetSum(double x = 1, double y = 1) { return x + y; } static double GetSum(string x = "1", string y = "1") { double dblX = Convert.ToDouble(x); double dblY = Convert.ToDouble(y); return dblX + dblY; } // ----- ENUM ----- // ----- ENUM ----- // An enum is a custom data type with // key value pairs. They allow you to // use symbolic names to represent data // The first number is 0 by default unless // you change it // You can define the underlying type // or leave it as int as default enum CarColor : byte { Orange = 1, Blue, Green, Red, Yellow } static void PaintCar(CarColor cc) { Console.WriteLine("The car was painted {0} with the code {1}", cc, (int)cc); } } } |
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