C# Function

Function is a block of code that has a signature. Function is used to execute statements specified in the code block. A function consists of the following components:

Function name: It is a unique name that is used to make Function call.

Return type: It is used to specify the data type of function return value.

Body: It is a block that contains executable statements.

Access specifier: It is used to specify function accessibility in the application.

Parameters: It is a list of arguments that we can pass to the function during call.

Syntax

FunctionName()
{
// function body
// return statement
}

Access-specifier, parameters and return statement are optional.

Let's see an example in which we have created a function that returns a string value and takes a string parameter.

using no parameter and return type

A function that does not return any value specifies void type as a return type. In the following example, a function is created without return type.

Example

snippet

using System;
namespace FunctionExample
{
    class Program
    {
        // User defined function without return type
        public void Show() // No Parameter
        {
            Console.WriteLine("This is non parameterized function");
            // No return statement
        }
        // Main function, execution entry point of the program
        static void Main(string[] args)
        {
            Program program = new Program(); // Creating Object
            program.Show(); // Calling Function           
        }
    }
}

Output

This is non parameterized function

using parameter but no return type

Example

snippet

using System;
namespace FunctionExample
{
    class Program
    {
        // User defined function without return type
        public void Show(string message)
        {
            Console.WriteLine("Hello " + message);
            // No return statement
        }
       // Main function, execution entry point of the program
        static void Main(string[] args)
        {
            Program program = new Program(); // Creating Object
            program.Show("Rahul Kumar"); // Calling Function           
        }
    }
}

Output

Hello Rahul Kumar

A function can have zero or any number of parameters to get data. In the following example, a function is created without parameters. A function without parameter is also known as non-parameterized function.

using parameter and return type

Example

snippet

using System;
namespace FunctionExample
{
    class Program
    {
        // User defined function
        public string Show(string message)
        {
         Console.WriteLine("Inside Show Function");
         return message;
        }
        // Main function, execution entry point of the program
        static void Main(string[] args)
        {
            Program program = new Program();
            string message = program.Show("Rahul Kumar");
            Console.WriteLine("Hello "+message);
        }
    }
}

Output

Inside Show Function Hello Rahul Kumar