Program : [ Click Here ]

1. Frame Number  : fno
2. Number of Pages  : count
3. Actual Pages : arr[100]

void accept()
{
int i;
printf("nEnter the number of Frames : ");
scanf("%d",&fno);

printf("nEnter the number of Pages : ");
scanf("%d",&count);

printf("nEnter the Page No : ");
for(i=0;i< count;i++)
    scanf("%d",&arr[i]);
}
Step 2 :
Now we have Pages and Frame Size.
 Total Number of Pages is Given by Variable : “Count“.
Logic :
Now We are Creating Circular Linked List Whose Size is equal to “Frame Size“
Initialize Each Node’s Data = -99.
-99 Tells us That Place is Empty
Call Create Function. 
Size of Linked List = Frame Size
Step 3 :
After Creating Initial Setup Call Function : fifo().
While Inserting Element in Frame [i.e in Linked List ] We have to Check Whether -
Page number is Already Present or Not.
There is Empty Location or not.
temp = start;  //Temporary Purpose
last = start;  //Replacement Purpose
curr = start;  //Current Purpose ->-99
We have To insert Total Number of Pages = “Value Specified in Count” so we requires 1 for loop.
for(i=0;i< count;i++)
Check Whether First Page is already Present or not.
res = search(arr[i]);
If Page is Present then Don’t Take any Action , and Read Next Page.
But If Page is Present then we have to insert Page in Linked List
Step 4 :
if(res == 0)
     {
     fault++;
     if(curr->data == -99)
        {
        curr->data = arr[i];
        curr = curr->next;
        }
     else
        {
        last ->data = arr[i];
        last = last->next;
        }
     }//end outer if
If Linked List have Blank Space then First “If Part” gets Executed.
If Linked List doesn’t have Blank Space then Overwrite on the Oldest Node. [ “last”  is used for Keeping Track of Oldest Node , After Overwriting Move “last” one position ahead. ]

Program for FIFO Page Replacement : Explanation [Click Here]

/*---------------------------------------------
Title : Page Replacement Algorithms
Program Developed By : Pritesh Abhiman Taral
----------------------------------------------*/

#include<stdio.h>
#include<conio.h>
#include<alloc.h>

struct node
  {
  int data;
  struct node *next;
  }*curr,*new_node,*current,*start=NULL,*temp,*last;

int arr[100],count,fault,fno;
//--------------------------------
void creat()
 {
 int i;
   
   for(i=0;i< fno;i++)
   {
   new_node=(struct node *)malloc(sizeof(struct node));
   new_node->data = -99;     // -99 = NULL or Empty Characcter
   new_node->next=NULL;
    
   if(start==NULL)
     {
     start=new_node;
     current=new_node;
     }
   else
     {
     current->next=new_node;
     current=new_node;
     }
   }
 current->next = start;
 }
//--------------------------------
void display()
{
struct node *temp;
temp=start;
  do
   {
   if(temp->data == -99)
       printf("-t",temp->data);
   else
       printf("%dt",temp->data);
   temp=temp->next;
   }while(temp!=start);
}
//--------------------------------
int search(int number)
{
int flag;
struct node *temp;
temp=start;
  do
   {
   if(temp->data==number)
         return(1);
   else
         flag = 0;
   temp=temp->next;
   }while(temp!=start);

if(flag ==0)
   return(0);
}
//--------------------------------
void fifo()
{
int res,i;
temp = start;  //Temp Purpose
last = start;  //Repl Purpose
curr = start;  //Curr Purpose ->-99

for(i=0;i< count;i++)
  {
  res = search(arr[i]);

   if(res == 0)
     {
     fault++;
     if(curr->data == -99)
        {
        curr->data = arr[i];
        curr = curr->next;
        }
     else
        {
        last ->data = arr[i];
        last = last->next;
        }
     }//end outer if

  printf("nnAfter Inserting (%d)  :: ",arr[i]);
  display();
  printf("    Fault : %d",fault);
  }//end for

printf("n--------------------------------------------n");
  printf(" ¯ Total Number of Faults = %d",fault);
printf("n--------------------------------------------n");

}
//--------------------------------
void accept()
{
int i;
printf("nEnter the number of Frames : ");
scanf("%d",&fno);

printf("nEnter the number of Pages : ");
scanf("%d",&count);

printf("nEnter the Page No : ");
for(i=0;i< count;i++)
    scanf("%d",&arr[i]);
}
//------------------------------------------------
void main()
{
char ch;
clrscr();
printf("nAccept Frame Number and Pages");
printf("n");

accept();
creat();
fifo();

getch();
}
Explanation :  [Click Here]
Output :
Accept Frame Number and Pages

Enter the number of Frames : 3

Enter the number of Pages : 7

Enter the Page No : 1 3 2 1 3 4 2


After Inserting (1)  :: 1  -  -      Fault : 1

After Inserting (3)  :: 1  3  -      Fault : 2

After Inserting (2)  :: 1  3  2      Fault : 3

After Inserting (1)  :: 1  3  2      Fault : 3

After Inserting (3)  :: 1  3  2      Fault : 3

After Inserting (4)  :: 4  3  2      Fault : 4

After Inserting (2)  :: 4  3  2      Fault : 4
═══════════════════════════════════════════════
 » Total Number of Faults = 4
═══════════════════════════════════════════════
Explanation :  [Click Here]