about constructor parameter

Question

Class My_class{
private:
Int k
}
\*If i declare a constructor with a parameter to input*\

My_class(int r){
k=r
}

\*Then, what if I create an object without entering the parameter*\
My_class obj

Answer 1

Compile error happens. No matching call for constructor with 0 parameters

Answer 2

Thank you

Answer 3

To prevent compile error, you can either do a parameter with a default value, or add a constructor with no parameter