what does this code do??

//6. Write a c program to simulate LRU page replacement algorithm
// for N frames and n pages. Print the page faults for each page.
#include<bits/stdc++.h>
using namespace std;

int main(){
    int n;
    cout<<"Enter number of pages: ";
    cin>>n;
    int pages[n];
    cout<<"Enter the pages: ";
    for(int i=0;i<n;i++)
        cin>>pages[i];
    int f;
    cout<<"Enter number of frames: ";
    cin>>f;
    int frames[f];
    for(int i=0;i<f;i++)
        frames[i]=-1;
    int top=-1;
    int page_faults=0;
    for(int i=0;i<n;i++){
        int flag=0;
        for(int j=0;j<f;j++){
            if(frames[j]==pages[i]){
                flag=1;
                break;
            }
        }
        if(flag==0){
            page_faults++;
            if(top==f-1){
                for(int j=0;j<f-1;j++)
                    frames[j]=frames[j+1];
                frames[top]=pages[i];
            }
            else{
                top++;
                frames[top]=pages[i];
            }
        }
        else{
            int index;
            for(int j=0;j<f;j++){
                if(frames[j]==pages[i]){
                    index=j;
                    break;
                }
            }
            int temp=frames[index];
            for(int j=index;j<f-1;j++)
                frames[j]=frames[j+1];
            frames[top]=temp;
        }
        cout<<"Page Faults: "<<page_faults<<endl;
        cout<<"Frames: ";
        for(int j=0;j<f;j++)
            cout<<frames[j]<<" ";
        cout<<endl;
    }
    cout<<"Total page faults: "<<page_faults<<endl;
    return 0;
}


give me some test cases to check it