How to deal with generic types?

Question

C++ / C#

I read an article about delegates. Everything seems to be clear, but there were generalized types that I didn’t fully understand. At an intuitive level, the connections in the code are clear, but ...

delegate T Operation<T, K>(K val);
 
class Program
{
    static void Main(string[] args)
    {
        Operation<decimal, int> op = Square;
 
        Console.WriteLine(op(5));
        Console.Read();
    }
 
    static decimal Square(int n)
    {
        return n * n;
    }
}

If you specifically say the line:
delegate T Operation<T, K>(K val);
then you get something like: "We declare a delegate with a return value of type T, which is called Operation, and the delegate's parameters are a val value of type K". Correctly? Where to fasten Operation in this phrase. What is <T, K>? Well, it is clear that it indicates what types are used in the Operate delegate, but what is it called? Explain in Russian, please.

Answer 1

Generics are when you expect certain types to be used in a context and you need to bind them according to certain criteria. It also saves you the hassle of having to type cast later in your code.
As an example, task: You need to implement class A with property F, which can be any type implemented from interface IB:
Solution 1. Non-optimized approach without generics:

class A {
  IB F { get; }
}

A a = new A();
C c = a.F as C; // Здесь придется приводить к типу.

Solution 2: Generic option:

class A<T> {
  T F { get; }
}

A<C> a = new A<C>();
C c = a.F; // Здесь лежит сразу экземпляр типа C, приводить к типу не нужно.