Page Replacement Algorithm

a) FIFO:

AIM: A program to simulate FIFO Page Replacement Algorithm

PROGRAM:

#include<stdio.h>

#include<conio.h>

void main()

{

int a[5],b[20],n,p=0,q=0,m=0,h,k,i,q1=1;

char f='F';

clrscr();

printf("Enter the Number of Pages:");

scanf("%d",&n);

printf("Enter %d Page Numbers:",n);

for(i=0;i<n;i++)

scanf("%d",&b[i]);

for(i=0;i<n;i++)

{if(p==0)

{

if(q>=3)

q=0;

a[q]=b[i];

q++;

if(q1<3)

{

q1=q;

}

}

printf("\n%d",b[i]);

printf("\t");

for(h=0;h<q1;h++)

printf("%d",a[h]);

if((p==0)&&(q<=3))

{

printf("-->%c",f);

m++;

}

p=0;

for(k=0;k<q1;k++)

{

if(b[i+1]==a[k])

p=1;

}

}

printf("\nNo of faults:%d",m);

getch();

}

OUTPUT:

Input:

Enter the Number of Pages: 12

Enter 12 Page Numbers:

2 3 2 1 5 2 4 5 3 2 5 2

Output:

2 2-> F

3 23-> F

2 23

1 231-> F

5 531-> F

2 521-> F

4 524-> F

5 524

3 324-> F

2 324

5 354-> F

2 352-> F

No of faults: 9

--------------------------
b) LRU:
AIM: A program to simulate LRU Page Replacement Algorithm

PROGRAM:

#include<stdio.h>
#include<conio.h>
void main()
{
int g=0,a[5],b[20],p=0,q=0,m=0,h,k,i,q1=1,j,u,n;
char f='F';
clrscr();
printf("Enter the number of pages:");
scanf("%d",&n);
printf("Enter %d Page Numbers:",n);
for(i=0;i<n;i++)
scanf("%d",&b[i]);
for(i=0;i<n;i++)
{if(p==0)
{
if(q>=3)
q=0;
a[q]=b[i];
q++;
if(q1<3)
{
q1=q;
//g=1;
}
}
printf("\n%d",b[i]);
printf("\t");
for(h=0;h<q1;h++)
printf("%d",a[h]);
if((p==0)&&(q<=3))
{
printf("-->%c",f);
m++;
}
p=0;
g=0;
if(q1==3)
{
for(k=0;k<q1;k++)
{
if(b[i+1]==a[k])
p=1;
}
for(j=0;j<q1;j++)
{
u=0;
k=i;
while(k>=(i-1)&&(k>=0))
{
if(b[k]==a[j])
u++;
k--;
}
if(u==0)
q=j;
}
}
else
{
for(k=0;k<q;k++)
{
if(b[i+1]==a[k])
p=1;
}
}
}
printf("\nNo of faults:%d",m);
getch();
}

OUTPUT:  
Input:
Enter the Number of Pages: 12
Enter 12 Page Numbers:
2 3 2 1 5 2 4 5 3 2 5 2

Output:
2  2-> F
3  23-> F
2  23
1  231-> F
5  251-> F
2  251
4  254-> F
5  254
3  354-> F
2  352-> F
5  352
2  352

No of faults: 7