CODEWITHSUNDEEP
c++data-structuresqueue
jmasterx
jmasterx

Reputation: 54103

Removing the first element from a queue?

I have a queue. If it exceeds X size, when I push an element I want to remove the first element of the queue. (the last element that would get popped and the first element pushed in)

void ClientPlayerManager::queueTableMessage( const std::string& playerName, const std::string& message )
{
    m_tableQ.push(std::make_pair(playerName,message));

    if(m_tableQ.size() > m_maxTableMessages)
    {
        //m_tableQ.pop_back(); does not exist
    }
}

Is there a way to do this with a std queue?

Thanks

Upvotes: 2

Views: 8853

Answers (2)

Ben Voigt
Ben Voigt

Reputation: 283614

If you want to remove an element from the opposite end from what pop does, just skip pushing it in the first place:

if(m_tableQ.size() < m_maxTableMessages) {
    m_tableQ.push(std::make_pair(playerName,message));
}

Upvotes: 0

templatetypedef
templatetypedef

Reputation: 372714

You can use a std::deque instead of a std::queue, which supports push_front, push_back, pop_front, and pop_back. This also allows for random access throughout, but you can just ignore that and treat the deque like a double-ended queue. (In fact, deque is short for double-ended queue).

Hope this helps!

Upvotes: 6

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