This program illustrates the essential difference between sets and multisets. First we create an empty set of integers, then we try to insert multiple copies of the same value into that set. Only a single copy of each value goes into the set, thus showing that the values stored in a set are unique. Press Enter to continue ... We being by trying to insert 1 twice and 2 once, each time ignoring the return value of the call to insert(). Press Enter to continue ... After this, the values in the set are: 1 2 Press Enter to continue ... Next we try to insert 3, then 4 twice, and finally 5, each time using the return value of insert() to report on the result. Press Enter to continue ... 3 inserted 4 inserted 4 not inserted 5 inserted Press Enter to continue ... After these attempts the set contents are: 1 2 3 4 5 Press Enter to continue ... Now we create an empty multiset of integers, and then try to insert multiple copies of the same value (two copies of 1, oneof 2 and 3, three of 4, and one of 5), and note that this time all values are actually inserted, showing that a multiset can hold duplicat copies. Press Enter to continue ... Here are the values in the mulitset: 1 1 2 3 4 4 4 5 Press Enter to continue ...