how to write this in c++, the pseudo code is availble already

------------------------------------------------------------

// Helper method for completions().

//

// Suggested base cases:

// If root is nullptr, return.

// If the last entry of the suggestions array is not "", return.

// (since completions() has already found 5 suggestions).

//

// Suggested recursive case:

// -If left subtree can contain strings that start with x,

// recurse on left subtree.

// -If root's string starts with x,

// add root->s to first empty location in results.

// -If right subtree can contain strings that start with x,

// recurse on right subtree.

void completions_recurse(string x, string* suggestions, Node* root);