X a(i, j);
|[i,j) is a valid range.
||Creates an associative container that contains all elements in the range [i,j).
||size() is equal to the distance from i to j. Each element in [i, j) is present in the container.
||Inserts t into a.
||The size of a is incremented by 1. The value of a.count(t) is incremented by a.
|[i, j) is a valid range.
||Equivalent to a.insert(t) for each object t that is pointed to by an iterator in the range [i, j) . Each element is inserted into a.
||The size of a is incremented by j – i.