Re: composition and bad_alloc

mpho wrote:
> Hi all,
> 
> This seems straightforward but gives this runtime error: terminate
> called after throwing an instance of 'std::bad_alloc' , what() :
> std9bad_alloc . I have:

There are several errors in your code which make that it does not
compile. There is also another error: you use array new in the
constructor, but do not use array delete in the destructor. Below is a
corrected version of your code. No runtime error occurs when I run it.
That said, I would use std::vector or tr1::array, rather than making
something like this myself.

#include <cassert> // added
typedef double T;  // added

class X {
      int sz;
      T *ptr;

     // added copy constructor and assignment operator, because
     // default ones don't make sense.
      X(X const &);
      X& operator=(X const &);
   public:
     X(int s, T *p) : sz(s), ptr(new T[s])
     {
         assert(ptr != 0);
         // for (int i = 0, i < sz; i++)
         for (int i = 0; i < sz; i++) // comma should be semicolon
             ptr[i] = p[i];
     }

     //~X() {  delete ptr;  ptr = 0;  }
     ~X() {  delete [] ptr;  ptr = 0;  } // array delete needed
};

class Y {
     X xobj;  // semicolon added
   public:
     Y(int s, T *p) : xobj(s, p) {  }
                 ~Y() { }
};

int main(){
     T ar[10] = {0.3};
     Y yobj(10, ar);
}

-- 
      [ See http://www.gotw.ca/resources/clcm.htm
for info about ]
      [ comp.lang.c++.moderated.    First time posters: Do this! ]