WAP TO IMPLIMENT LFU PAGE REPLACEMENT ALGORITHM.

#include<stdio.h>

int n;

main()

{

int seq[30],fr[5],pos[5],find,flag,max,i,j,m,k,t,s,pf=0;

int count=1,p=0;

float pfr;

clrscr();

printf("Enter no of pages:");

scanf("%d",&max);

printf("Enter the reference string:");

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

  scanf("%d",&seq[i]);

printf("Enter no of frames:");

scanf("%d",&n);

fr[0]=seq[0];

pf++;

printf("\n%d  ",fr[0]);

i=1;

while(count<n)

{

flag=1;

p++;

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

{

if(seq[i]==seq[j])

flag=0;

}

if(flag!=0)

{

fr[count]=seq[i];

printf("%d  ",fr[count] );

count++;

pf++;

}

i++;

}

printf("\n");

for(i=p;i<max;i++)

{

flag=1;

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

{

if(seq[i]==fr[j])

flag=0;

}

if(flag!=0)

{

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

{

m=fr[j];

for(k=i;k<max;k++)

{

if(seq[k]==m)

{

pos[j]=k;

break;

}

else

pos[j]=-1;

}

}

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

{

if(pos[k]==-1)

flag=0;

}

if(flag!=0)

s=findmax(pos);

if(flag==0)

{

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

{

if(pos[k]==-1)

{

s=k;

break;

}

}

}

pf++;

fr[s]=seq[i];

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

printf("%d  ",fr[k]);

printf("\n");

}

}

pfr=(float)pf/(float)max;

printf("\nThe no of page faults are %d",pf);

getch();

}

int findmax(int a[])

{

int max,i,k=0;

max=a[0];

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

{

if(max<a[i])

{

max=a[i];

k=i;

}

}

return k;

}

program for FIFO page replacement algorithm

#include<iostream.h>

#include<conio.h>

void main()

{

clrscr();

int n,flag=0,a[30],b[30],i,j,count=0,f,fault=0;

cout<<"\n**** FIFO page replacement algorithm ****\n";

cout<<"\n enter no. of pages ";

cin>>n;

cout<<" \n enter the reference string ";

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

cin>>b[i];

cout<<"enter frame :";

cin>>f;

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

{

for(j=0;j<f;j++)

{

if(a[j]==b[i])

{

flag=0;

break;

}

else

{

flag=1;

}

}

if(flag==1)

{

a[count]=b[i];

count++;

fault++;

 if(count==f)

  {

  count= 0;

  }

}

}

cout<<"total page faults are :"<<fault;

getch();

}

program for LRU page replacement algorithm .

#include<iostream.h>

#include<conio.h>

void main()

{

clrscr();

int q[20],p[50],c=0,c1,d,f,i,j,k=0,n,r,t,b[20],c2[20];

cout<<"Enter no of pages:";

cin>>n;

cout<<"Enter the reference string:";

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

cin>>p[i];

cout<<"Enter no of frames:";

cin>>f ;

q[k]=p[k];

cout<<"\n "<<q[k]<<"\n";

c++;

k++;

for(i=1;i<n;i++)

{

c1=0;

 for(j=0;j<f;j++)

{

 if(p[i]!=q[j])

c1++;

}

if(c1==f)

c++;

if(k<f)

{

q[k]=p[i];

k++;

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

cout<<" "<<q[j];

cout<<"\n";

}

else

{

for(r=0;r<f;r++)

{

c2[r]=0;

for(j=i-1;j<n;j--)

{

if(q[r]!=p[j])

c2[r]++;

else

break;

}

}

for(r=0;r<f;r++)

 b[r]=c2[r];

for(r=0;r<f;r++)

{

for(j=r;j<f;j++)

{

if(b[r]<b[j])

{

t=b[r];

b[r]=b[j];

b[j]=t;

}

}

}

for(r=0;r<f;r++)

{

if(c2[r]==b[0])

q[r]=p[i];

cout<<" "<<q[r];

}

cout<<"\n";

}

}

}

cout<<"\nThe no of page faults is "<<c;

getch();
}

Producer Consumer Problem

#include<iostream.h>

#include<conio.h>

#include<process.h>

void main()

{

void display(int c,int stack[]);

 int ch,n,c1=0,c2=0,produce[23],consume[23];

 clrscr();

 cout<<"\n\n\n\n\n\t\n\n\t\t\tEnter Stack Size :  "<<n;

 cin>>n;

 while(1)

 {

   clrscr();

   cout<<"\t\tProducer Stack (Stack Size :"<<n<<")\n\t\t~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~";

   display(c1,produce);

   cout<<"\n\n\t\tConsumer Stack (Stack Size :" <<n<<")\n\t\t~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~";

   display(c2,consume);

   cout<<"\n\t\tCHOICES\n\t\t~~~~~~~\n\t1.Producer\n\t2.Consumer\n\t3.Exit\nEnter your choice :  ";

   cin>>ch;

   switch(ch)

   {

    case 1:

                  if(c1==n)

                   cout<<"Produer stack is FULL.So Producer goes to SLEEP\n";

                  else

                  {

                  c1++;

                  cout<<"\t\tEnter PRODUCE item is :";

                  cin>>produce[c1];

                  }

                  break;

    case 2:

                  if(c2==n)

                     cout<<"Consumer Stack is FULL.So it goes to SLEEP!..........\n\tReset the Cosumer Stack\n",c2=0;

                  else if(c1==0)

                    cout<<"\tProducer stack is EMPTY\n";

                  else

                   {

                   c2++;

                   consume[c2]=produce[c1];

                   cout<<"\t\tCONSUME one item";

                   c1--;

                   }

                  break;

    case 3:

                  exit(0);

    default:

                  cout<<"\tIt is Wrong choice,Please enter correct choice!............\n";

    }

   getch();

  }

}

void  display(int c,int stack[])

 {

  int i;

  cout<<"\n-----------------------------------------------------------------------------\n";

  if(c==0)

  cout<<"\tStack is EMPTY\n\t\t(Now It is sleeping)";

  else

  for(i=1;i<=c;i++)

  cout<<stack[i]<<"   ";

  cout<<"\n-------------------------------------------------------------------------------\n";

getch();

  }

OPTIMAL PAGE REPALCEMET

#include<conio.h>
#include<iostream.h>
int fr[3];
void main()
{
clrscr();
int p[50],i,j,fs[20],n;
int max,found=0,lg[3],index,k,l,flag1=0,flag2=0,pf=0,f;
cout<<"\n **** OPTIMAL PAGE REPLACEMENT ALGORITHM ****\n"
cout<<"-----------------------------------------------" ;
cout<<"\n \nenter the no. of pages : \n";
cin>>n;
cout<<"enter the reference string : \n";
for(i=0;i<n;i++)
cin>>p[i];
cout<<"\n enter the no. of frames : \n";
cin>>f;
for(i=0;i<f;i++)
{
fr[i]=-1;
}
for(j=0;j<n;j++)
{
flag1=0;
flag2=0;
for(i=0;i<f;i++)
{
if(fr[i]==p[j])
{
flag1=1;
flag2=1;
break;
}
}
if(flag1==0)
{
for(i=0;i<f;i++)
{
if(fr[i]==-1)
{
fr[i]=p[j];
flag2=1;
break;
}
}
}
if(flag2==0)
{
for(i=0;i<f;i++)
lg[i]=0;
for(i=0;i<f;i++)
{
for(k=j+1;k<n;k++)
{
if(fr[i]==p[k])
{
lg[i]=k-j;
break;
}
}
}
found=0;
for(i=0;i<f;i++)
{
if(lg[i]==0)
{
index=i;
found=1;
break;
}
}
if(found==0)
{
max=lg[0];
index=0;
for(i=1;i<f;i++)
{
if(max<lg[i])
{
max=lg[i];
index=i;
}
}
}
fr[index]=p[j];
pf++;
}
}
cout<<"\n no of page faults : "<<pf+f;
getch();
}

PROGRAM OF ROUND ROBIN SCHEDULING

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

void main()
{

char pid[10];
int cpu[5];
int i,j,k,t=0,ts;
clrscr();
printf("\t\t\tROUND ROBIN\n\n\n");
printf("Enter time slice:");
scanf("%d",&ts);
printf("\n");
for(i=0;i<5;i++)
{
printf("Enter Process %d name :",i+1);
scanf("%s",&pid[i]);
printf("Enter Process %d CPU  :",i+1);
scanf("%d",&cpu[i]);
printf("\n\n");
}
for(i=0;i<5;i++)
{

for(j=0;j<5;j++)
{
if(cpu[j]>1)
{
if(cpu[j]<ts)
{
   printf("\t%d-%c-%d",t,pid[j],t+cpu[j]);
t=t+cpu[j];
}
if(cpu[j]>=ts)
{
//for(k=0;k<ts;k++)
printf("\t%d-%c-%d",t,pid[j],t+ts);
t=t+ts;
}
}
if(cpu[j]==1)
{
cpu[j]=cpu[j]-1;
printf("\t%d-%c-%d",t,pid[j],t+1);
t=t+1;
}
cpu[j]=cpu[j]-ts;
}
printf("\n\n");
}
getch();
}

PROGRAM FOR PRIORITY(PRIMITIVE) SCHEDULING

#include<stdio.h>
#include<conio.h>
void main()
{
char pname[5];
int cpu[5],rq[5],at[5],prty[5],pq[5]={100,100,100,100,100};
int i ,t,min,f=0,p,j,total=0;
clrscr();
printf("\t\t\tPRIORITY(PRIMITIVE)\n\n\n");
for(i=0;i<5;i++)
{
printf("enter process %d name       :",i+1);
scanf("%s",&pname[i]);
printf("enter process %d cpu time      :",i+1);
scanf("%d",&cpu[i]);
printf("enter process %d priority      :",i+1);
scanf("%d",&prty[i]);
printf("enter process %d arrival time  :",i+1);
scanf("%d",&at[i]);
printf("\n\n");
}
for(i=0;i<5;i++)
{
total=total+cpu[i];
}
for(t=0;t<total;t++)
{
for(i=0;i<5;i++)
{
if(at[i]<=t)
{
rq[i]=cpu[i];
pq[i]=prty[i];
}

}
min=50;
for(j=0;j<5;j++)
{
if(pq[j]<=min && rq[j]!=0)
{
min =pq[j];
p=j;
}

}
rq[p]=rq[p]-1;
printf("\t");
printf("%d-%c-%d",t,pname[p],t+1);
printf("\t");
cpu[p]=rq[p];

}
getch();
}