Program 12a):

AIM: To implement page replacement algorithms FIFO (First In First Out)

 

#include<stdio.h>

#include<conio.h>

int i,j,nof,nor,flag=0,ref[50],frm[50],pf=0,victim=-1;

void main()

{

 clrscr();

 printf("\n \t\t\t FIFI PAGE REPLACEMENT ALGORITHM");

 printf("\n Enter no.of frames....");

 scanf("%d",&nof);

 printf("Enter number of reference string..\n");

 scanf("%d",&nor);

 printf("\n Enter the reference string..");

 for(i=0;i<nor;i++)

 scanf("%d",&ref[i]);

 printf("\nThe given reference string:");

 for(i=0;i<nor;i++)

 printf("%4d",ref[i]);

 for(i=1;i<=nof;i++)

 frm[i]=-1;

 printf("\n");

 for(i=0;i<nor;i++)

 {

   flag=0;

   printf("\n\t Reference np%d->\t",ref[i]);

   for(j=0;j<nof;j++)

   {

     if(frm[j]==ref[i])

     {

       flag=1;

       break;

     }}

      if(flag==0)

   {

     pf++;

     victim++;

     victim=victim%nof;

     frm[victim]=ref[i];

     for(j=0;j<nof;j++)

     printf("%4d",frm[j]);

   }

 }

 printf("\n\n\t\t No.of pages faults...%d",pf);

 getch();

}

OUTPUT:

Program 12b):

AIM: To implement page replacement algorithm LRU (Least Recently Used)

#include<stdio.h>

#include<conio.h>

int i,j,nof,nor,flag=0,ref[50],frm[50],pf=0,victim=-1;

int recent[10],lrucal[50],count=0;

int lruvictim();

void main()

{

  clrscr();

  printf("\n\t\t\t LRU PAGE REPLACEMENT ALGORITHM");

  printf("\n Enter no.of Frames....");

  scanf("%d",&nof);

  printf(" Enter no.of reference string..");

  scanf("%d",&nor);

  printf("\n Enter reference string..");

  for(i=0;i<nor;i++)

  scanf("%d",&ref[i]);

  printf("\n\n\t\t LRU PAGE REPLACEMENT ALGORITHM ");

  printf("\n\t The given reference string:");

  printf("\n………………………………..");

  for(i=0;i<nor;i++)

  printf("%4d",ref[i]);

  for(i=1;i<=nof;i++)

  {

    frm[i]=-1;

    lrucal[i]=0;

  }

  for(i=0;i<10;i++)

   recent[i]=0;

   printf("\n");

   for(i=0;i<nor;i++)

   {

     flag=0;

     printf("\n\t Reference NO %d->\t",ref[i]);

     for(j=0;j<nof;j++)

     {

      

        if(frm[j]==ref[i])

       {

           flag=1;

           break;

       }

     }

     if(flag==0)

     {

       count++;

       if(count<=nof)

       victim++;

       else

       victim=lruvictim();

       pf++;

       frm[victim]=ref[i];

       for(j=0;j<nof;j++)

       printf("%4d",frm[j]);

     }

     recent[ref[i]]=i;

   }

   printf("\n\n\t No.of page faults...%d",pf);

   getch();

}

int lruvictim()

{

  int i,j,temp1,temp2;

  for(i=0;i<nof;i++)

  {

    temp1=frm[i];

    lrucal[i]=recent[temp1];

  }

  temp2=lrucal[0];

  for(j=1;j<nof;j++)

  {

    if(temp2>lrucal[j])

    temp2=lrucal[j];

  }

  for(i=0;i<nof;i++)

  if(ref[temp2]==frm[i])

  return i;

  return 0;

}

OUTPUT:

                        

Program 12c):

AIM: To implement page replacement algorithms Optimal (The page which is not used for longest time)

#include<stdio.h>

#include<conio.h>

int i,j,nof,nor,flag=0,ref[50],frm[50],pf=0,victim=-1;

int recent[10],optcal[50],count=0;

int optvictim();

void main()

{

   clrscr();

   printf("\n OPTIMAL PAGE REPLACEMENT ALGORITHN");

   printf("\n.................................");

   printf("\nEnter the no.of frames");

   scanf("%d",&nof);

   printf("Enter the no.of reference string");

   scanf("%d",&nor);

   printf("Enter the reference string");

   for(i=0;i<nor;i++)

       scanf("%d",&ref[i]);

   clrscr();

   printf("\n OPTIMAL PAGE REPLACEMENT ALGORITHM");

   printf("\n................................");

   printf("\nThe given string");

   printf("\n....................\n");

   for(i=0;i<nor;i++)

       printf("%4d",ref[i]);

   for(i=0;i<nof;i++)

   {

       frm[i]=-1;

       optcal[i]=0;

   }

   for(i=0;i<10;i++)

       recent[i]=0;

   printf("\n");

   for(i=0;i<nor;i++)

   {

      flag=0;

      printf("\n\tref no %d ->\t",ref[i]);

      for(j=0;j<nof;j++)

      {

          if(frm[j]==ref[i])

          {

             flag=1;

             break;

          }

      }

      if(flag==0)

      {

          count++;

          if(count<=nof)

              victim++;

          else

              victim=optvictim(i);

          pf++;

          frm[victim]=ref[i];

          for(j=0;j<nof;j++)

             printf("%4d",frm[j]);

      }

   }

   printf("\n Number of page faults: %d",pf);

   getch();

}

int optvictim(int index)

{

   int i,j,temp,notfound;

   for(i=0;i<nof;i++)

   {

      notfound=1;

      for(j=index;j<nor;j++)

          if(frm[i]==ref[j])

          {

              notfound=0;

              optcal[i]=j;

              break;

          }

      if(notfound==1)

             return i;

   }

   temp=optcal[0];

   for(i=1;i<nof;i++)

       if(temp<optcal[i])

             temp=optcal[i];

   for(i=0;i<nof;i++)

       if(frm[temp]==frm[i])

             return i;

 return 0;

}