Generics

A Generic is a way to declassify the type of variable used, e.g. if there was a function to add up two integer values, but you had two double values, then the int function would not function correctly, so there would be a need to function overload the function to allow for the double increment as well. But just envisage that the same function would be required for characters, floats, personally created ones etc, then there would be more functions per type of variable than the actual work done.

A generic class negates this by allowing any class type passed to the function, as long as the type has the standard increment process defined, it will work with any type.

This will demonstrate the basics of the generics.

using System;
 
// create a class with a generic type of T (e.g. pass in the type of your choice
public class GenTest<T>;
{
       // the private value
       private T genericValue;
 
       // default constructor for the class (same name as the class)
       // ~ is the deconstructor
       public GenTest(T generic) 
       {
              genericValue = generic;       // set the internal T = passed value
       }
 
       // return the value of the internal value
       public T ReturnValue()
       {
              return genericValue;
       }
}
 
public class MainProgram
{
       static void Main()
       {
              // create a integer type class, with the default value of 2
              GenTest<int> genInt = new GenTest<int>(2);
              Console.WriteLine("Int generic = " + genInt.ReturnValue());
 
              // same class create a string with the default value of "cool"
              GenTest<string> genString = new GenTest<string>("cool");
              Console.WriteLine("String generic = " + genString.ReturnValue());
       }
}

If you save the code and run with .net 2 or greater (.NET Framework) ( since this was part of .net 2 and not with .net 1). The output will be

Int generic = 2
String generic = cool

As you can see the same class is able to use both integer and strings as the default variable type.

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