Can I please get someone's help to fully comment this code,

// Program to compare the efficiency of FIFO, LRU, LFU, Optimal algorithm  #include int* lru(int n, int *p, int f) { int q[f],pgfaultcnt=0,c1,d,i,j,k=0,r,t,b[f],c2[f]; static int PFcount[] = {0,0,0,0,0}; q[k]=p[k]; pgfaultcnt++; k++; for(i=1;iif(i%2000 == 0) { PFcount[((i/2000)-1)] = pgfaultcnt; printf(" LRU : %d = %d", i, pgfaultcnt); } c1=0; for(j=0;jif(p[i]!=q[j]) c1++; } if(c1==f) { pgfaultcnt++; if(kelse { for(r=0;rfor(j=i-1;jif(q[r]!=p[j]) c2[r]++; else  break; } } for(r=0;rfor(r=0;rfor(j=r;jif(b[r]for(r=0;rif(c2[r]==b[0]) q[r]=p[i]; } } } } PFcount[4] = pgfaultcnt; printf(" LRU : Total no of page faults %d",pgfaultcnt); return PFcount; } int* fifo(int n, int *a, int no) { int i,j,frame[no],k,avail,pgfaultcnt=0; static int PFcount[] = {0,0,0,0,0}; for(i=0;ifor(i=1;i<=n;i++) { if(i%2000 == 0) { PFcount[((i/2000)-1)] = pgfaultcnt; printf(" FIFO : %d = %d", i, pgfaultcnt); } avail=0; for(k=0;kif(frame[k]==a[i]) avail=1; if (avail==0){ frame[j]=a[i]; j=(j+1)%no; pgfaultcnt++; } } printf(" FIFO : Total no of page faults %d",pgfaultcnt); return PFcount; } int isHit(int data, int nf, int *p) { int hit=0,j; for( j=0; jif(p[j]==data) { hit=1; break; } } return hit; } int getHitIndex(int data, int nf, int *p) { int hitind; int k; for( k=0; kif(p[k]==data) { hitind=k; break; } } return hitind; } int* optimal(int n, int *in, int nf) { int p[nf]; int hit=0, i,j,k, pgfaultcnt=0; static int PFcount[] = {0,0,0,0,0}; int near[nf]; for(i=0; ifor(i=0; iif(i%2000 == 0 && i > 0) { PFcount[((i/2000)-1)] = pgfaultcnt; printf(" OPTM : %d = %d", i, pgfaultcnt); } if(isHit(in[i], nf, p)==0) { for(j=0; jint pg=p[j]; int found=0; for(k=i; kif(pg==in[k]) { near[j]=k; found=1; break; } else  found=0; } if(!found) near[j]=9999; } int max=-9999; int repindex; for(j=0; jif(near[j]>max) { max=near[j]; repindex=j; } } p[repindex]=in[i]; pgfaultcnt++; } } PFcount[4] = pgfaultcnt; printf(" OPTM : Total no of page faults:%d",pgfaultcnt); return PFcount; } int* lfu(int n, int *in, int nf) { int p[nf]; int hit=0,i,j,k; int pgfaultcnt = 0; static int PFcount[] = {0,0,0,0,0}; int usedcnt[nf]; int least,repin,sofarcnt=0,bn; pgfaultcnt=0; for(i=0; ifor(i=0; ifor(i=0; iif(i%2000 == 0 && i > 0) { PFcount[((i/2000)-1)] = pgfaultcnt; printf(" LFU : %d = %d", i, pgfaultcnt); } if(isHit(in[i], nf, p)) { int hitind=getHitIndex(in[i],nf, p); usedcnt[hitind]++; } else { pgfaultcnt++; if(bnelse { least=9999; for(k=0; kif(usedcnt[k]for(k=0; k<=i; k++) if(in[i]==in[k]) sofarcnt=sofarcnt+1; usedcnt[repin]=sofarcnt; } } } PFcount[4] = pgfaultcnt; printf(" LFU : Total no of page faults:%d",pgfaultcnt); return PFcount; } int main() { FILE * fp, *in; in = fopen("input.txt","r+"); fp = fopen ("output.txt", "w+"); int n = 10000; int p[n]; int f = 512; printf("Enter No. of Frames : "); scanf("%d",&f); if(f != 128 && f!= 256 && f!= 512 && f!= 1024) { printf("Invalid Frame Size  Running The Program with Default Frame Size "); f = 512; } // Reading 10000 pages  int i = 0; while(!feof(in)) { fscanf(in,"%d",&p[i]); i++; } fclose(in); // Running Algorithms  int *pf_lru = lru(n,p,f); // get the number of page faults for LRU  int *pf_fifo = fifo(n,p,f); // get the number of page faults for FIFO  int *pf_lfu = lfu(n,p,f); // get the number of page faults for LFU  int *pf_oa = optimal(n,p,f); // get the number of page faults for Optimal   printf(" Completed : 10000 Pages"); // Write it in the file output.txt  fprintf(fp," ============================================================================== "); fprintf(fp,"PAGE REPLACEMENT ALGORITHMS(FRAME_SIZE = %d) ",f); fprintf(fp,"============================================================================== "); fprintf(fp,"Algorithm\tTotal page faults\t2000\t4000\t6000\t8000\t10000 "); fprintf(fp," ------------------------------------------------------------------------------ "); fprintf(fp," FIFO\t\t%4d\t\t%4.4f\t\t%4.4f\t\t%4.4f\t\t%4.4f\t\t%4.4f",pf_fifo[4],(pf_fifo[0]/(2000.0)),(pf_fifo[1]/(4000.0)),(pf_fifo[2]/(6000.0)),(pf_fifo[3]/(8000.0)),(pf_fifo[4]/(10000.0))); fprintf(fp," LRU\t\t%4d\t\t%4.4f\t\t%4.4f\t\t%4.4f\t\t%4.4f\t\t%4.4f",pf_lru[4],(pf_lru[0]/(2000.0)),(pf_lru[1]/(4000.0)),(pf_lru[2]/(6000.0)),(pf_lru[3]/(8000.0)),(pf_lru[4]/(10000.0))); fprintf(fp," LFU\t\t%4d\t\t%4.4f\t\t%4.4f\t\t%4.4f\t\t%4.4f\t\t%4.4f",pf_lfu[4],(pf_lfu[0]/(2000.0)),(pf_lfu[1]/(4000.0)),(pf_lfu[2]/(6000.0)),(pf_lfu[3]/(8000.0)),(pf_lfu[4]/(10000.0))); fprintf(fp," Optimal\t\t%4d\t\t%4.4f\t\t%4.4f\t\t%4.4f\t\t%4.4f\t\t%4.4f",pf_oa[4],(pf_oa[0]/(2000.0)),(pf_oa[1]/(4000.0)),(pf_oa[2]/(6000.0)),(pf_oa[3]/(8000.0)),(pf_oa[4]/(10000.0)));    printf(" Completed : EVERYTHING"); fclose(fp); return 0; } 

please?