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In this non-compliant code example, the resources associated with the object pointed to by pst are not recovered in the event that processItem throws an exception, thereby potentially causing a resource leak.

while (moreToDo) {
  SomeType *pst = new SomeType();
  try {
    pst->processItem();
  }
  catch (...) {
    // deal with exception
    throw;
  }
  delete pst;
}

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In this code, the exception handler recovers the resources associated with the object pointed to by pst.

while (moreToDo) {
  SomeType *pst = new SomeType();
  try {
    pst->processItem();
  }
  catch (...) {
    // deal with exception
    delete pst;
    throw;
  }
  delete pst;
}

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A better approach would be to employ RAII. This forces every object to 'clean up after itself' in the face of abnormal behavior, preventing the programmer from having to do so. A judicious unique_ptr would free the resource whether an error occurs or not.

while (moreToDo) {
  std::unique_ptr<SomeType> pst = new SomeType();
  try {
    pst->processItem();
  }
  catch (...) {
    // deal with exception
    throw; // pst automatically freed
  }
  // pst automatically freed
}

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