Question

I want a simple yet efficient circular buffer/queue. If I use std::vector, I have to do this:

if ( v.size() >= limit ) {
    std::vector<int> it = v.begin();
    v.insert( it, data );
    v.erase( it+1 );
}

Is there any simpler solution?

Answer 1

You want to maintain the size of the buffer, overwriting older items. Just overwrite the old ones as time goes on. If you want to deal with the case where nItems < limit, then you would need to deal with that, this is just a simple example of using modulo to insert into a fixed size buffer.

std::vector<int> data(10);

for (int i = 0 ; i < 100 ; ++i)
{
    data[i%10] = i;
}

for (std::vector<int>::const_iterator it = data.begin() ; it !=data.end(); ++it)
{
     std::cout << *it << std::endl;
}

That method of insertion will keep the last 10 elements in the buffer.