Inheritance in generic types

Question

Can anyone help me in using Where for generic types? I was trying to create a function which does ST with a number of type double or int, so I said it should be generic function. But when I try to assign a value to variables of that generic type, I can't because it's not a numerical type. Also, I can't use Where to inherit generic type from int or double data types.

Here is the code:
public static T[,] Unit(int n) where T : PROBLEM
{

    T[,] mat = new T[n, n];  

    for (int i = 0; i < n; i++)   
        mat[i, i] = (T)1;      

    return mat;

}

Can anyone help?

Answer 1

Unfortunately one of the shortcomings of C# is that you cannot easily make generic numerical algorithms. You can kind of hack around it, like using this example from MSDN:

public abstract class BaseCalculator<T>
{
   public abstract T Add(T arg1,T arg2);
   public abstract T Subtract(T arg1,T arg2);
   public abstract T Divide(T arg1,T arg2);
   public abstract T Multiply(T arg1,T arg2);
}
public class IntCalculator : BaseCalculator<int>
{
   public override int Add(int arg1, int arg2)
   {
      return arg1 + arg2;
   }
   //Rest of the methods 
} 

But generally speaking the .Net libraries just have a separate implementation for this sort of thing rather than attempting to use generics.