How to Remove Elements from a `std::vector` During Iteration Without Invalidating Iterators?

Efficient Removal of Elements from a std::vector During Iteration

Question:

How can one efficiently remove elements from a std::vector while iterating over it without invalidating existing iterators? Consider the following scenario:

<code class="cpp">std::vector<std::string> m_vPaths;
for (auto iter = m_vPaths.begin(); iter != m_vPaths.end(); iter++) {
    if (::DeleteFile(iter->c_str())) {
        m_vPaths.erase(iter);  // Invalidates remaining iterators
    }
}</code>

Answer:

The erase() method provided by std::vector invalidates iterators. To avoid this issue, one can utilize the return value of erase() which points to the next valid iterator:

<code class="cpp">std::vector<std::string>::iterator iter;
for (iter = m_vPaths.begin(); iter != m_vPaths.end(); ) {
    if (::DeleteFile(iter->c_str()))
        iter = m_vPaths.erase(iter);  // Sets iter to next valid element
    else
        ++iter;
}</code>

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