C# 抽象 class 设计，是否可以在抽象 class 中放置一个构造函数并调用基础来访问它们

Question

I was practicing c# abstract class and inheritance, but I was wondering if derived classes could access the constructor by calling the base

public abstract class A
{
    protected bool value_A;
    protected int value_B;
    public A(int input)
    {
      A = true;
      B = false;
    }
    public abstract int function_B();
  }

}
public class childA : A
{
    public childA (int input):base(input)
    { 
    }
    public override int function_B()
    {
      //do smth
    }   
}
public class childB : A
{
    public childB(int input):base(input)
    {   
    }
    public override int function_B()
    {
      //do something different
    }
    public void functionC(int input)
    {
        
    }   
}

I was confused if I should use this abstract class design or just go ez by using inheritance -> declare a virtual function in class A.

Answer 1

1. Yes, you can. Derived class c'tor can call base class one, even if the base class is abstract.
2. Generally, using abstract base class makes sense if there is a common functionality (or traits) that you want to reuse, and instantiating the base class does not make sense (and therefore you make it an abstract class). A basic example is "Shapes" hierarchy, with abstract base class Shape that has color and center (for instance) and virtual method Draw, and all specific shapes inheriting from Shape and implementing the actual Draw functionality for each specific shape.