Question

Take a variable length struct (if this were a real program, an int array would be better):

#include <vector>
struct list_of_numbers(){
  int length;
  int *numbers; //length elements.
};
typedef std::vector<list_of_numbers> list_nums; //just a writing shortcut

(...)

And build a vector out of it:

list_nums lst(10); //make 10 lists.
lst[0].length = 7; //make the first one 7 long.
lst[0].X = new int[7]; //allocate it with new[]

(...)

The above works for g++ in ubuntu. The new() calls are needed to avoid segfaults. Can the lst vector be deleted all at once when it is no longer needed, or will the new calls cause a memory leak? It would be tedious to manually delete() all of the parts called with new().

Answer 1

In general, you would want to put cleanup code in the destructor of the object (~list_of_numbers()) and memory creating code in the constructor (list_of_numbers()). That way these things are handled for you when the destructor is called (or when the object is created).