In this section, we will write a program that reads multiple word strings from a standard input, and then we will use std::next_permutation to generate and print all the permutations of those strings:

1. First things first again; we include all the necessary headers and declare that we use the std namespace:

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

      using namespace std;

2. We begin with a vector of strings, which we feed with the whole standard input. The next step is sorting the vector:

      int main()
      {
          vector<string> v {istream_iterator<string>{cin}, {}};
          sort(begin(v), end(v));

3. Now, we print the vector's content on the user terminal. Afterward, we call std::next_permutation. It systematically shuffles the vector to generate a permutation of its items, which we then print again. The next_permutation will return false as soon as the last permutation was reached:

          do {
              copy(begin(v), end(v), 
                   ostream_iterator<string>{cout, ", "});
              cout << 'n';
          } while (next_permutation(begin(v), end(v)));
      }

4. Let's compile and run the function with some example input:

      $ echo "a b c" | ./input_permutations 
      a, b, c, 
      a, c, b, 
      b, a, c, 
      b, c, a, 
      c, a, b, 
      c, b, a,