Parameter

A parameter is a fundamental element in programming that serves as a placeholder within the declaration of a function or method. It acts as a variable that receives values passed into the function when it is called.  

By defining parameters, developers can create functions that accept different inputs and perform specific tasks based on those inputs. Parameters significantly enhance code flexibility, reusability, and customisation, making them an essential concept to grasp for any programmer.

An example of a parameter written in C#

Below we show an example of a parameter written in C#.

// Function declaration with a parameter

void GreetUser(string name)

{
    Console.WriteLine("Hello, " + name + "!");
}

// Calling the function and passing a value for the parameter

GreetUser("John");

We have a function called GreetUser that accepts a parameter named name of type string. The function prints a greeting message, and the name is provided as the parameter. When calling the GreetUser function and passing the value "John" as the argument for the name parameter, it will output: "Hello, John!".

Types of parameters

In programming, different parameters provide flexibility and customisation options when defining functions.  We have listed a few types below.

Positional parameters

Positional parameters are defined in a specific order and receive values based on their position when calling a function. This means the values provided must match the order and number of parameters defined. 

Keyword parameters

Keyword parameters allow values to be assigned to specific parameters using names when calling a function, regardless of their order. This enhances code readability and provides more flexibility in passing arguments. 

Default parameters

Default parameters have predefined values assigned to them, simplifying function calls by eliminating the need to provide values for all parameters.  

Variable-length parameters

Variable-length parameters enable functions to accept a random number of arguments. This is useful when the number of parameters required may vary or is unknown in advance.  

Understanding the different types of parameters empowers programmers to design functions that can handle various input scenarios effectively.