我可以从列表中获取对象并进行复制，但是如何删除复制的对象？

Question

I'm trying to find all the processes in the blockedProcess list with the specified event number, copy them into a transferList, and then remove them. Copying and moving the Process objects works fine, but I can't figure out how to remove those Process objects from blockedProcess afterwards.

ProcessQueue findEventFlag(int eventnum)
{
    ProcessQueue transferProcess;
    Process process;
    list<Process>::iterator it;



    for (it = blockedProcess.begin(); it != blockedProcess.end(); it++)
    {
        process = *it;

        if (process.getEvent() == eventnum)
        {
            process.setState("READY");
            process.setEvent(-1);
            transferProcess.enqueue(process);
        }

    }

    return transferProcess;

}

Answer 1

Building on the comments, try this (which relies on the fact that std::list::erase conveniently returns an iterator to the next item in the list):

ProcessQueue findEventFlag(int eventnum)
{
    ProcessQueue transferProcess;
    Process process;
    list<Process>::iterator it = blockedProcess.begin();

    while (it != blockedProcess.end())
    {
        process = *it;

        if (process.getEvent() == eventnum)
        {
            process.setState("READY");
            process.setEvent(-1);
            transferProcess.enqueue(process);
            it = process.Erase (it);
        }
        else
            it++;
    }

    return transferProcess;
}

You can also transfer an element from one list to another with std::list::splice which would avoid copying your process object and might therefore be more efficient, something like:

ProcessQueue findEventFlag(int eventnum)
{
    ProcessQueue transferProcess;
    Process process;
    list<Process>::iterator it = blockedProcess.begin();

    while (it != blockedProcess.end())
    {
        process = *it;
        list<Process>::iterator next = std::next (it);

        if (process.getEvent() == eventnum)
        {
            process.setState("READY");
            process.setEvent(-1);
            transferProcess.splice(transferProcess.begin (), blockedProcess, it);
        }

        it = next;
    }

    return transferProcess;
}