"Second Attack"

[Analeea]

Please help me find a mistake in the algorithm, like everything works right, but sometimes there's a mistake with different input data. So I've decided to implement the algorithm of the second attempt. Shortly about the task, there's a memory of a limited size, and the pages, the algorithm of FIFO, unlike if the page is in memory, it's translated at the end of the queue. I've got a page that's in memory and removed from her position, and the page is added at the end of the line (if they match).

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <deque>
#include <algorithm>
#include <utility>
#include <cstdlib>
void show_fifo(const deque<int> &dq)

{

deque<int>::const_iterator i;

for (i=dq.begin(); i != dq.end(); ++i)

{

cout << *i << " ";

}

cout << endl;

}

int main()

{

int mem_size = 5;

int access_num;

access_num = 13;

int array[] = { 1, 2, 3, 4, 5, 2, 3, 4, 1, 5, 4, 1, 3};
cout &lt;&lt; "Vtoraya popbitka: " &lt;&lt; endl;
// Vtoraya popitka
    deque&lt;int&gt; dq;

    for (int i=0; i&lt;mem_size; i++)
    {
            dq.push_back(-1);
    }
    cout &lt;&lt; "Memory: " &lt;&lt; endl;
    show_fifo(dq);

    for (int i = 0; i &lt; access_num; ++i)
    {
            cout &lt;&lt; "Step " &lt;&lt; (i+1) &lt;&lt; ":" &lt;&lt; endl;
            for (int j = 0; j &lt; dq.size(); j++)
            {
                            if ((find(dq.begin(), dq.end(), array[i]) != dq.end()) &amp;&amp; (dq.size() != 0))
                            {       
                                    cout &lt;&lt; "Page: " &lt;&lt; array[i] &lt;&lt; " has in memory" &lt;&lt; endl;
                                    int del = dq.at(array[i]);
                                    dq.erase(dq.begin()+del);
                                    dq.push_front(array[i]);
                                    break;
                            }
                            else
                            {
                                    dq.push_front(array[i]);
                                    dq.pop_back();
                                    break;
                            }
            }
            show_fifo(dq);
    }

[juvenalb]

If I understand the code correctly, you're checking whether there is. array[i] Total dqand if there is, "replace him at the end of the line, by removing and putting him to the end. If that's what you're saying:

    for (int j = 0; j < dq.size(); j++)
    {
        deque<int>::iterator ii = find(dq.begin(), dq.end(), array[i]);
    if ( ii != dq.end() )
    {       
        cout &lt;&lt; "Page: " &lt;&lt; array[i] &lt;&lt; " has in memory" &lt;&lt; endl;
        dq.erase(ii);
        dq.push_front(array[i]);
        break;
    }
    else
    {
        dq.push_front(array[i]);
        dq.pop_back();
        break;
    }
}

You already have a terator to indicate where to remove why to reshape from.

int del = dq.at(array[i]);

dq.erase(dq.begin()+del);

?
(I understand this place is falling)

By the way, placing at the end of the queue through removal/supply is not optimal, it's easier to do.

        deque<int>::iterator ii = find(dq.begin(), dq.end(), array[i]);

    if ( ii != dq.end() )
    {       
        cout &lt;&lt; "Page: " &lt;&lt; array[i] &lt;&lt; " has in memory" &lt;&lt; endl;

        deque&lt;int&gt;::reverse_iterator temp = dq.rbegin(); // получить итератор на последний элемент
        std::swap(*ii, *temp); // обменять значения итераторов

        break;
    }