页面置换算法FIFO代码

以下是FIFO页面置换算法的C++实现代码：

#include<iostream>
#include<queue>
using namespace std;

int main()
{
    int pages[20], frames[10], total_pages, total_frames, faults = 0, i, j;
    bool flag;
    queue<int> q;

    cout<<"Enter total number of pages: ";
    cin>>total_pages;

    cout<<"Enter the page reference string: ";
    for(i=0; i<total_pages; i++)
        cin>>pages[i];

    cout<<"Enter total number of frames: ";
    cin>>total_frames;

    for(i=0; i<total_frames; i++)
        frames[i] = -1;  // initialize all frames to -1

    cout<<endl<<"FIFO Page Replacement Process:"<<endl;

    for(i=0; i<total_pages; i++)
    {
        flag = false;

        // check if page is already present in frame
        for(j=0; j<total_frames; j++)
        {
            if(frames[j] == pages[i])
            {
                flag = true;
                break;
            }
        }

        if(!flag)
        {
            frames[q.front()] = pages[i];  // replace the oldest page
            q.pop();
            q.push(i % total_frames);  // add new page to queue
            faults++;
        }

        cout<<"Page "<<pages[i]<<":\t";

        for(j=0; j<total_frames; j++)
        {
            if(frames[j] != -1)
                cout<<frames[j]<<" ";
            else
                cout<<"- ";
        }

        cout<<"\tFaults: "<<faults<<endl;
    }

    cout<<"\nTotal Page Faults: "<<faults<<endl;

    return 0;
}

代码中使用了一个队列来记录最早进入帧的页面，并在需要替换页面时将它们的位置弹出。