How to pass control to another constructor?

Question

C++ / C#

Let's say I have a class:

public class test
{
   int _IntValue;
   string _StringValue;

   public test(int i)
   {
       _IntValue=i;
   }

   public test(int i, string s)
   {
       //тут надо бы выполнить код из первого конструктора
       _StringValue = s + _IntValue;
   }
}

How can I make it so that when the second constructor is called, the code from the first one is executed first, and only then from the second one (well, or vice versa, it doesn’t matter) I’m
interested in the option without implementation through inheritance or through highlighting the code of the first constructor into a separate procedure.
Thank you.

Answer 1

public test(int i, string s) : this(i)
{
    _StringValue = s + _IntValue;
}

Answer 2

public class test
{
   int _IntValue;
   string _StringValue;

   public test(int i)
   {
       _IntValue=i;
   }

   public test(int i, string s)
   {
       //тут надо бы выполнить код из первого конструктора
       this.test(i);

       _StringValue = s + _IntValue;
   }
}