How does the Set data structure ensure the absence of duplicate elements?

The Set data structure ensures the absence of duplicate elements through an internal mechanism that checks the uniqueness of each added element. Typically, Set is implemented using a hash table or a balanced tree, which allows for quick determination of whether an element already exists in the set.

When adding an element to a Set:

• The hash code of the element is computed (if a hash table is used).
• It checks whether an element with the same value already exists.
• If the element already exists, the new one is not added.
• If the element does not exist, it is added to the structure.

Thus, Set guarantees that each element appears only once, which is convenient for storing unique values.