C++20 STL Cookbook/

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Generate Permutations of Data Sequences

Generate Permutations of Data Sequences

Learn to generate permutations of data sequences.

We'll cover the following...

There are many use cases for permutations, including testing, statistics, research, and more. The next_permutation() algorithm generates permutations by re-ordering a container to the next lexicographical permutation. permutation

How to do it

For this recipe, we will print out the permutations of a set of three strings:

  • We'll start by creating a short function for printing the contents of a container:

void printc(const auto& c, string_view s = "") {
    if(s.size()) cout << format("{}: ", s);
    for(auto e : c) cout << format("{} ", e);
    cout << '\n';
}

We'll use this simple function to print our data set and permutations.

  • In the main() function, we declare a vector of string objects and sort it with the sort() algorithm.

int main() {
    vector<string> vs{ "dog", "cat", "velociraptor" };
    sort(vs.begin(), vs.end());
    ...
}

The next_permutation() ...