How to do it...

In this section, we will fill an std::vector with random words, sort it, and then insert more words while keeping the vector's sorted word order intact.

1. Let's first include all headers we're going to need.

      #include <iostream>
      #include <vector>
      #include <string>
      #include <algorithm>
      #include <iterator> 
      #include <cassert>

1. We also declare that we are using namespace std in order to spare us some std:: prefixes:

      using namespace std;

1. Then we write a little main function, which fills a vector with some random strings.

      int main()
      {
          vector<string> v {"some", "random", "words", 
                            "without", "order", "aaa", 
                            "yyy"};

1. The next thing we do is sorting that vector. Let's do that with some assertions and the is_sorted function from the STL before, which shows that the vector really was not sorted before, but is sorted afterward.

          assert(false == is_sorted(begin(v), end(v)));
          sort(begin(v), end(v));
          assert(true == is_sorted(begin(v), end(v)));

1. Now, we finally add some random words into the sorted vector using a new insert_sorted function, which we still need to implement afterward. These words shall be put at the right spot so that the vector is still sorted afterward:

          insert_sorted(v, "foobar");
          insert_sorted(v, "zzz");

1. So, let's now implement insert_sorted a little earlier in the source file.

      void insert_sorted(vector<string> &v, const string &word)
      {
          const auto insert_pos (lower_bound(begin(v), end(v), word));
          v.insert(insert_pos, word);
      }

1. Now, back in the main function where we stopped, we can now continue printing the vector and see that the insert procedure works:

          for (const auto &w : v) { 
              cout << w << " ";
          }
          cout << '\n';
      }

1. Compiling and running the program yields the following nicely sorted output:

      aaa foobar order random some without words yyy zzz