Methods In C-Sharp (C#)

Methods In C-Sharp (C#)

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  C# LECTURE Abid Kohistani GC MadyanSwat
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  Methods A method isa block of code which only runs when it is called. You can pass data, known as parameters, into a method. Methods are used to perform certain actions, and they are also known as functions. Why use methods? To reuse code: define the code once, and use it many times.
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  Create a Method Amethod is defined with the name of the method, followed by parentheses (). C# provides some pre-defined methods, which you already are familiar with, such as Main(), but you can also create your own methods to perform certain actions: class Program { static void MyMethod() { // code to be executed } } Syntax MyMethod() is the name of the method static means that the method belongs to the Program class and not an object of the Program class. You will learn more about objects and how to access methods through objects later in this tutorial. void means that this method does not have a return value. You will learn more about return values later in this chapter Note: In C#, it is good practice to start with an uppercase letter when naming methods, as it makes the code easier to read.
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  Call a Method Tocall (execute) a method, write the method's name followed by two parentheses () and a semicolon; In the following example, MyMethod( ) is used to print a text (the action), when it is called: static void MyMethod() { Console.WriteLine("I just got executed!"); } static void Main(string[] args) { MyMethod(); } // Outputs "I just got executed!" Example 1 static void MyMethod() { Console.WriteLine("I just got executed!"); } static void Main(string[] args) { MyMethod(); MyMethod(); MyMethod(); } // I just got executed! // I just got executed! // I just got executed! Example 2 A method can be called multiple times:
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  Parameters and Arguments Informationcan be passed to methods as parameter. Parameters act as variables inside the method. They are specified after the method name, inside the parentheses. You can add as many parameters as you want, just separate them with a comma. The following example has a method that takes a string called fname as parameter. When the method is called, we pass along a first name, which is used inside the method to print the full name: When a parameter is passed to the method, it is called an argument. So, from the example above: fname is a parameter, while Liam, Jenny and Anja are arguments. static void MyMethod(string fname) { Console.WriteLine(fname + " Refsnes"); } static void Main(string[] args) { MyMethod("Liam"); MyMethod("Jenny"); MyMethod("Anja"); } // Liam Refsnes // Jenny Refsnes // Anja Refsnes
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  Default Parameter Value Youcan also use a default parameter value, by using the equals sign (=). If we call the method without an argument, it uses the default value ("Norway"): static void MyMethod(string country = "Norway") { Console.WriteLine(country); } static void Main(string[] args) { MyMethod("Sweden"); MyMethod("India"); MyMethod(); MyMethod("USA"); } // Sweden // pakistan// Norway // USA Example A parameter with a default value, is often known as an "optional parameter". From the example above, country is an optional parameter and "Norway" is the default value.
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  Multiple Parameters You canhave as many parameters as you like: Note that when you are working with multiple parameters, the method call must have the same number of arguments as there are parameters, and the arguments must be passed in the same order. static void MyMethod(string fname, int age) { Console.WriteLine(fname + " is " + age); } static void Main(string[] args) { MyMethod("Liam", 5); MyMethod("Jenny", 8); MyMethod("Anja", 31); } // Liam is 5 // Jenny is 8 // Anja is 31 Example
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  Return Values The voidkeyword, used in the examples above, indicates that the method should not return a value. If you want the method to return a value, you can use a primitive data type (such as int or double) instead of void, and use the return keyword inside the method: This example returns the sum of a method's two parameters: static int MyMethod(int x) { return 5 + x; } static void Main(string[] args) { Console.WriteLine(MyMethod(3)); } // Outputs 8 (5 + 3) Example static int MyMethod(int x, int y) { return x + y; } static void Main(string[] args) { Console.WriteLine(MyMethod(5, 3)); } // Outputs 8 (5 + 3) static int MyMethod(int x, int y) { return x + y; } static void Main(string[] args) { int z = MyMethod(5, 3); Console.WriteLine(z); } // Outputs 8 (5 + 3) You can also store the result in a variable (recommended, as it is easier to read and maintain):
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  Named Arguments It isalso possible to send arguments with the key: value syntax. That way, the order of the arguments does not matter: static void MyMethod(string child1, string child2, string child3) { Console.WriteLine("The youngest child is: " + child3); } static void Main(string[] args) { MyMethod(child3: "John", child1: "Liam", child2: "Liam"); } // The youngest child is: John Example
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  Method Overloading With methodoverloading, multiple methods can have the same name with different parameters: static int PlusMethod(int x, int y) { return x + y; } static double PlusMethod(double x, double y) { return x + y; } static void Main(string[] args) { int myNum1 = PlusMethod(8, 5); double myNum2 = PlusMethod(4.3, 6.26); Console.WriteLine("Int: " + myNum1); Console.WriteLine("Double: " + myNum2); } Example
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