Completing the GenMethods class

For the next stage, you can say the following. Enter it within a set of curly braces below this line:

if(x.CompareTo(y) < 0)

Now, why do we write this? We write this because if you right-click on the CompareTo method and select Go To Definition in the drop-down menu (F12), you can see that it's defined inside the IComparable interface. If you expand that and look at what it returns, it says: Values Meaning Less than zero This instance precedes obj in the sort order., as shown in Figure 2.2.2:

In other words, in our context, this means that x and y are related in the following sense.

If the value returned by CompareTo is less than 0, then x is less than y.

Now, enter the following within a set of curly braces beneath the preceding line:

return $"<br>{x}<{y}"; 

In this line, you return and actually format a string, so that it's more than just a simple comparison. So, for example, you can say here x is less than y.

The other possibility is the reverse. Now, enter the following beneath the earlier closed curly brace:

else
{
     return $"<br>{x}>{y}";
} 

If you want to know more about CompareTo, right-click on it and select Go To Definition in the drop-down menu (F12). As seen under Returns in Figure 7.2.3, it says: Zero This instance occurs in the same position in a sort order as obj. Greater than zero This instance follows object in the sort order.:

In the if (x.CompareTo(y) < 0) line, this instance signifies the x variable and object denotes the y variable.

So, this is the basic GenMethods class. The final version of the GenMethods.cs file, including comments, is shown in the following code block:

using System;
public class GenMethods
{
    //method can operate on multiple data types
    public static void Swap<T>(ref T x, ref T y)
    {
        T temp = x; //save x
        x = y;//assign y to x
        y = temp;//assign original value of x back to y
    }
    //this function has a constraint, so it can operate on values
    //that can be compared
    public static string Compare<T>(T x, T y) where T :IComparable
    {
        //CompareTo returns < 0, =0,or >0, depending on the relationship
        //between x and y
        if(x.CompareTo(y)<0)
        {
            return $"<br>{x}<{y}";
        }
        else
        {
            return $"<br>{x}>{y}";
        }
    }
} 

As you can see, the GenMethods class contains a couple of generic functions because it can operate on different data types, except for the second CompareTo method, which is a slightly more restricted version, meaning that a constraint is applied of the IComparable type.