C++ In a Nutshell

Name

next_permutation function template — Generates next permutation

Synopsis

template<typename BidiIter>
  bool next_permutation(BidiIter first, BidiIter last);
template<typename BidiIter, typename Compare>
  bool next_permutation(BidiIter first, BidiIter last, Compare comp);

The next_permutation function template rearranges the contents of the range [first, last) for the next permutation, assuming that there is a set of lexicographically ordered permutations. The return value is true if the next permutation is generated, or false if the range is at the last permutation, in which case the function cycles, and the first permutation is generated (that is, with all elements in ascending order).

Figure 13-9 shows all the permutations, in order, for a sequence. The next_permutation function swaps elements to form the next permutation. For example, if the input is permutation 2, the result is permutation 3. If the input is permutation 6, the result is permutation 1, and next_permutation returns false.

Figure 13-9. Permutations of a sequence

Example

Example 13-4 shows a simple program that prints all the permutations of a sequence of integers. You can use this program to better understand the next_permutation function template.

Example 13-4. Generating permutations

#include <algorithm> #include <iostream> #include <istream> #include <iterator> #include <ostream> #include <vector> void print(const std::vector<int>& ...