I am still quite new to class concept. I have a problem here. for example, i have a class called

class p{ 
       int id;
       p(id){
               //constructor

       }
}

now, i want to make instances of class p. After i have all the instances. i want to build a function get_p(pid) to return the specific class p which id=pid, how can i write this part?

I have read c++ and java class tutorials, but i cant sort this out. please help me.