How to to declare a static variable and increment it every time object of that class is created

Question

I want to declare a static variable and increment it every time object of that class is created. I am using C# and am new to it.

public class student
    {
        static int idcount;         /// for the number of objects created and to use it to assign lib nos
        public info biodata;               /// for making biadata easily available for both students and teachers
        record rec;

        public student(int i)           /////   ******* parameterised constructor for adding entry
        {
            rec = new record();
            biodata = new info();                //// new student record so everything is empty
            idcount++;                  /// new object created so incrementing static variable
            biodata.regno = idcount;
            rec.limit = 0;              /// indicating the number of books he has issued
        }

        public int getidcount()
        { return idcount; }
        public student()                /////local constructor for reading objects from file
        {
            rec = new record();
            biodata = new info();
            rec.limit = 0;
        }
/// methods 
}