pointer in a class

[mickey]

Hello,
I'm wondering when is necessary/better declare a pointer to an object in a class or a pointer to a vector in a class

class A {
  public:
   vector<flaoat> fvec;
   //or
  vector<float>* fpvec;
  A() {  
      fvec.resize(1000);
      //or
      fpvec = new vector<float>(1000);
  }
};

class A {
  public:
   vector<flaoat> fvec;
   //or
  vector<float>* fpvec;
  A() {  
      fvec.resize(1000);
      //or
      fpvec = new vector<float>(1000);
  }
};

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What's the thing that lead me to opt one or other?
THe same question if I had a Person p[10]; in the class. Should be better take a pointer to an array of person? How to choice?

thanks