MyQuickSort error code

MyQuickSort_error.cpp

// ---------------------------------------
template <class T> 
void Swap( std::vector<T>::iterator it1, std::vector<T>::iterator it2) {
  T temp = *it1;
  *it1 = *it2;
  *it2 = temp;
}

// -----------------------------------------
template <class T> 
void MyQuickSort( std::vector<T>::iterator begin, std::vector<T>::iterator end) {

  if( distance( begin, end) <= 1 ) { return; }
  
  std::vector<T>::iterator pivot = begin;
  // Swap( begin, pivot);   // since the first element is selected to be the pivot, swapping the pivot position is not necessary
  
  std::vector<T>::iterator it = begin;
  it++;
  std::vector<T>::iterator last = begin;
  for( ; it != end; it++) {
    if( *it <= *pivot) {
      last++;
      Swap( it, last);
    }
  }
  Swap( pivot, last);
  
  MyQuickSort( begin, last);
  MyQuickSort( ++last, end);
}