需要在while循环中中断

Question

I am writing a loop whereby if a queue is not empty, the loop will run, and I was just wondering if there was a need to include a break at the end of the loop. Essentially each loop should run for every single element in the queue until the queue is empty.

So which of the following should it be - I just don't know if there is a right thing to do.

while (1)
{

    /*process message from incoming queue*/
    if (!msgs_inc.empty())
    {
        /*categorise incoming message into global map of outgoing messages*/
        msgInfo current_msg = incMsgClassification(msgs_inc.front());
        msgs_inc.pop();

        clients_msg[current_msg.destID][current_msg.priorityLevel].push(current_msg);
    }
}

or

while (1)
{
    //Sleep(50000);
    //cout << "success" << endl;

    /*process message from incoming queue*/
    if (!msgs_inc.empty())
    {
        /*categorise incoming message into global map of outgoing messages*/
        msgInfo current_msg = incMsgClassification(msgs_inc.front());
        msgs_inc.pop();

        clients_msg[current_msg.destID][current_msg.priorityLevel].push(current_msg);
        break;
    }
}

Answer 1

What you want to do is more cleanly written as ..

while (!msgs_inc.empty()) // loop as long as queue still has elements
{    
    /*process message from incoming queue*/
    /*categorise incoming message into global map of outgoing messages*/
    msgInfo current_msg = incMsgClassification(msgs_inc.front());
    msgs_inc.pop();

    clients_msg[current_msg.destID][current_msg.priorityLevel].push(current_msg);
}

Or perhaps

while(1) {//infinite loop
    while (!msgs_inc.empty()) // loop as long as queue still has elements
    {    
        /*process message from incoming queue*/
        /*categorise incoming message into global map of outgoing messages*/
        msgInfo current_msg = incMsgClassification(msgs_inc.front());
        msgs_inc.pop();

        clients_msg[current_msg.destID][current_msg.priorityLevel].push(current_msg);
    }
}

This is more relevant if this function is running on a seperate thread, and is the only piece of code running on that thread.