Hash table as return type of a function in C++

问题

I would like to know if I can use Hash table as a return type of a function in C++. :)

回答1:

The C++ standard library implementation of a hash table is std::unordered_map and yes, you can happily return it from a function:

std::unordered_map<X, Y> foo() {
  std::unordered_map<X, Y> map;
  return map;
}

It can be copied because it has a copy constructor^†. If you implement your own hash table, it will also be returnable if it has a copy constructor.

^{† In C++11, a move constructor will be sufficient for the example given.}

来源：https://stackoverflow.com/questions/15114790/hash-table-as-return-type-of-a-function-in-c