Now, let's put a <T> symbol after where it says public class GenericsClass, as follows:

public class GenericsClass<T>

This means that this single class can work equally well with several different data types. Next, enter the following beneath the open curly brace under the preceding line:

private T[] vals;

Enter the following comment directly above this line:

//generic array instance variable

In other words, this will operate equally well on doubles, decimals, integers, and so on.

Now, in the following line, enter the following:

public GenericsClass(T[] input)

As you can see, you can also make parameters that are generic like this one. This is a parameter, input is the name of it, and the type is T. So, it's a generic array.

Next, enter the following between a set of curly braces beneath the preceding line:

vals = input;

Of course, you should be able to display these values. so, enter the following line beneath the closed curly brace under the vals = input; line:

public string DisplayValues()

To display these values, you'll enter the following between a set of curly braces beneath the preceding line.

First, put in a string, as follows:

string str = null;

Next, declare the string and initialize the value to null.

Then, enter the following directly below this line:

foreach ( T t in vals)

As you can see, the foreach loop here is going to operate. The T object will be a different data type, depending on how we choose to make the object. The t variable, of course, is each specific value inside the vals array.

Next, you will enter the following between a set of curly braces beneath the preceding line:

str += $"<br>Value={t}";

Remember, we use the += operator to accumulate and <br> to push down to the next line. To get the value, of course, we will put in the t variable.

At the end, you want to return this, so you will type the following beneath the closed curly brace under the preceding line:

return str;

That's it. The final version of the GenericsClass.cs file for this chapter, including comments, is shown in the following code block:

//<T> means this class can operate on many different data types
public class GenericsClass<T>
{
    //generic array instance variable
    private T[] vals;//array of T inputs
    public GenericsClass(T[] input)
    {
        //set value of instance variable
        vals = input;
    }
    public string DisplayValues()
    {
        string str = null;//create string to build up display
        foreach(T t in vals)
        {
            //actually accumulate stuff to be displayed
            str += $"<br>Value={t}";
        }
    //return string of outputs to calling code
    return str;
    }
}

Notice that we have a single block of code; this will now operate on integers, doubles, and so on.