取消引用结构向量的指针时出现c ++分段错误

Question

So I'm creating a closed-hashing hash table for a class and I have a structure

struct Example {
  string key;
  string data;

  Example() { key = "000"; }
};

and a class which contains a member that points to a vector of structures, a constructor, and a function I'll be using to illustrate the problem.

class hash_table {
  private:
  vector<Example>* hash;

  public:
  hash_table(int size);
  void dummy_method();
 };

It is meant to dynamically allocate the number of structures in the vector based on user/file input.

hash_table :: hash_table ( int size=10 )
{
  //initialize vector 
  vector<Example> * hash = new vector<Example>(size);
  //test objects
  for(int i=0;i<size;i++)
    cout<<(*hash)[i].key<<endl;
}

the above code appears to initialize the 10 members, as it prints out "000" ten times.

however, once I try this by calling dummy_method-

void hash_table::dummy_method() { 
  cout<<(*hash)[0].key<<endl;
} 

I get a segmentation fault

I'm pretty sure this isn't even the correct way to do this, but I've been looking/tinkering forever and I can't seem to find a solution. I absolutely have to use a pointer to a vector of structures however, and I'm pretty sure I'm supposed to be dynamically allocating each of those structures as well (somehow). Thanks for any help.

(also, yes, we actually HAVE to use namespace, thus no std anywhere)

Answer 1

vector<Example> * hash = new vector<Example>(size); expression will initialize a local variable with name hash , not a hash_table::hash member (which is left uninitialized).