std::list::erase not working

Question

I am trying to delete an element from a list of objects if one of the object\'s properties matches a condition. This is my function to do so, however, after performing this

Answer 1

The reason you see no changes reflected is that your list is not being passed by reference, so you are only removing elements from a copy of the list.

Change it to this:

void FileReader::DeleteProcess(int id, list &listToDeleteFrom) //note &

This will keep the same syntax in the function and modify the original.

However, the way you're deleting the elements is a bit sub-optimal. If you have C++11, the following will remove your invalidation problem, and is more idiomatic, using an existing algorithm designed for the job:

listToDeleteFrom.erase ( //erase matching elements returned from remove_if
    std::remove_if( 
        std::begin(listToDeleteFrom), 
        std::end(listToDeleteFrom), 
        [](const Process &p) { //lambda that matches based on id
            return p->ID == id;
        }
    ),
    std::end(listToDeleteFrom) //to the end of the list
);

Note the keeping of std::list<>::erase in there to actually erase the elements that match. This is known as the erase-remove idiom.