Summary  
This chapter covers defining a delegate type to represent methods with a specific signature and using that delegate to pass different functions as parameters.  

General domain of usage  
Statistical calculations on numeric arrays.

You can download the base code by cloning the <a 
href="https://github.com/Codefinity-Java/DelegatesTask"
target="_blank"
style="color: #ff8a00; font-weight: 600; text-decoration: none; transition: 0.3s ease-in-out;"
onmouseover="this.style.color='#ff0000'"
onmouseout="this.style.color='#d27204'">Github Repository</a>.

**Your task** is to define a delegate type called `Operation`, which can refer to the methods that have the same signature as the `max` and `avg` methods. 

Currently there is no delegate definition so the program doesn't compile, however after defining the delegate type you should be able to successfully compile and run the program, indicating that your solution is correct.

Note

Use the syntax <code>delegate &lt;return type&gt; &lt;type name&gt; &lt;parameter list&gt;</code> to define the delegate type.

Hint

```
using System.ComponentModel.DataAnnotations;

namespace DelegateIntro
{
    internal class Program
    {
        // Write code below this line
        delegate float Operation(int[] nums);
        // Write code above this line

        static void Main(string[] args)
        {
            int[] nums = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };

            Console.WriteLine(arrayMethod(max, nums));
            Console.WriteLine(arrayMethod(avg, nums));
        }

        static float arrayMethod(Operation opr, int[] nums)
        {
            return opr(nums);
        }
        
        static float max(int[] nums)
        {
            int max = nums[0];
            for(int i = 1; i &lt; nums.Length; i++)
                if (max &lt; nums[i])
                    max = nums[i];
            return max;
        }

        static float avg(int[] nums)
        {
            float sum = 0;
            for(int i = 0; i &lt; nums.Length; i++)
                sum += nums[i];
            return sum / nums.Length;
        }
    }
}    
```

Solution

In this course, we will learn about some advanced C# concepts along with MAUI, which is an application development library. We will learn how to create some interesting GUI applications while keeping them quick and responsive using techniques like Threading. We will make applications that will interact user input and APIs, and apart from that, we will cover some important C# concepts like Reflection and Generics. This course will further improve our programming skills and will give us a strong foundation to move forward towards Web Development.

In this section, we will learn what MAUI is, and how to set up a .NET MAUI application. We will also look at the structure of an MAUI application, and in the end, we will learn how to add some basic elements to our UI. This section will prepare us for the rest of the course where we will be working with more practical concepts.

In this section we will learn about delegates, events and data binding. Using this knowledge we will learn how to make interesting interactive GUI applications.

In this section, we will learn what Threading is and how to use it to keep our applications responsive, and run smoothly while performing resource intensive tasks. We will see how to differs from other similar concepts on C# and what are good practices when implementing Threading in our application. There will also be some interesting tasks to help us in understand this concept on a deeper level.

In this section, we will learn how to make more robust methods, classes and other objects which can work multiple types of input data types, by first learning about Generics and how to implement generic classes, then we will move on to Reflection and how to use reflection for further improving the capabilities of our programs.

Challenge: Defining Delegates