[Dev-C++] C++ constructor problems

[<mic...@la...>]

   Hello,

   I restart my C++ learning. For do this, I write some C++ classes. I 
made a first class 'Point'. I shall be use in the future, in other 
relative classes (triangle class, circle class, etc ...).

   The first derivate class are Point_1D, it runs good. The second 
inheritance from Point_1D to Point_2D do a lot of problemes with 
constructors. I wrote its into my sources (in the attachement). Can you 
say me what is wrong ?

   Thanks for your help !

PS.: I hope they are not off topics ! :o)