How do I iterate safely under modification with std::set in performance-sensitive code?

Iterating safely over a std::set in C++ when modifications may occur can be challenging. A common approach involves using iterators while being cautious about the modifications. In performance-sensitive code, it's critical to minimize overhead while ensuring that the iteration process is stable. One effective method is to gather the modifications in a temporary container, allowing the iteration to complete without interference.

Here’s a brief example illustrating how to safely iterate over a std::set while modifying it:


        #include 
        #include 
        #include 

        int main() {
            std::set mySet = {1, 2, 3, 4, 5};
            std::vector toRemove; // Vector to hold elements to remove
            
            // Initial iteration to collect elements to remove
            for (auto it = mySet.begin(); it != mySet.end(); ) {
                if (*it % 2 == 0) { // Condition for removal
                    toRemove.push_back(*it); // Collect element for later removal
                    it++; // Advance the iterator
                } else {
                    it++; // Advance the iterator
                }
            }
            
            // Now, perform the actual removal outside the iteration
            for (int num : toRemove) {
                mySet.erase(num);
            }
            
            // Display the modified set
            for (const auto &num : mySet) {
                std::cout << num << " ";
            }
            return 0;
        }

C++ std::set iterator modification performance-sensitive safe iteration

How do I iterate safely under modification with std::set in performance-sensitive code?

Popular Topics

Recent Languages

How do I iterate safely under modification with std::set in performance-sensitive code?

Related Questions

Popular Topics

Recent Languages