How to add elements of a std::set to another non-empty set?

Question

``` set<int> A, B; for (int i = 0; i < 100; i++) A.insert(i); for (int i = 50; i < 150; i++) B.insert(i); ``` How to add elements of set `B` to the set `A`? In another words, how to implement `A` = Union(`A`, `B`)?

Accepted Answer

By default sets are unique values only and sorted so inserting the iterator range should work:

```
A.insert(B.begin(), B.end());
```

How to add elements of a std::set to another non-empty set?

Solution

Problem