Question

C++ - How can I implement this function so that it uses smart pointers to release any dynamically allocated memory when member variables are destroyed? I want to use unique_ptr to do this.

bool CompactStringSet::insert(const std::string& value) {
Node* cur = &this->root_; // Start at the dummy "root" node.
for (auto character : value) { // For each character...
Node* search = this->FindNext(
cur, character); // ... find a child containing the character.
if (search) { // If such a node exists...
// cur = search; ... nothing to do. We just move on.
return false;
} else { // ... otherwise, we need to insert a new node.
Node* new_node = new Node{character};
if (cur->child) { // This node already has a child...
cur = cur->child; // ... so its child needs a sibling.
while (cur->sibling) cur = cur->sibling; // Find the last sibling...
cur->sibling = new_node; // ... and give it a new sibling.
} else {
cur->child = new_node; // This node is childless. Let's give it one.
}
cur = new_node;
}
}
if (!cur->terminal) { // If the stopping point was not already marked as
// terminal...
++this->num_strings_; // ... we inserted a new string
cur->terminal =
true; // ... and the stopping point needs to be marked as such.
return true;
}
return false;
}

Answer 1

You could modify your function as:-

First of all include a file :-

#include <memory> // for std::unique_ptr

Write the following line:-

std::unique_ptr<Node*> new_node(new Node{character});

instead of

Node* new_node = new Node{character};

This would automatically destroy(de-allocate the memory allocated) the variable named new_node whenever that variable goes out of scope .