[Dev-C++] ofstream error

[<qa...@ho...>]

Hi.

The following code 

void writeToFile(char* filename, vector<hashItem_rowCol*>& hashTable){
  ofstream ofile(filename);
 
  for(int i=3D0;i<hashTable.size();i++){
    if(hashTable[i] !=3D NULL){

      ...
   
    }
  }
}

produces the following error

Pattern_Creator.cpp:1555: variable `std::ofstream ofile' has initializer=
 but incomplete type

1) What does this error mean?
2) How do I correct it? 

Any clues?

regards,
J=F6rgen