EXPERIMENT-1
AIM: Write a program to illustrate First Come First Serve
Scheduling algorithm.
Program:
#include<iostream>
using namespace std;
int main()
{
int n,bt[20],wt[20],tat[20],avwt=0,avtat=0,i,j;
cout<<"Enter total number of processes(maximum 20):";
cin>>n;
cout<<"\nEnter Process Burst Time\n";
for(i=0;i<n;i++)
{
cout<<"P["<<i+1<<"]:";
cin>>bt[i];
}
wt[0]=0;
for(i=1;i<n;i++)
{
wt[i]=0;
for(j=0;j<i;j++)
wt[i]+=bt[j];
}
cout<<"\nProcess\t\tBurst Time\tWaiting Time\tTurnaround Time";
for(i=0;i<n;i++)
{
tat[i]=bt[i]+wt[i];
avwt+=wt[i];
avtat+=tat[i];
cout<<"\nP["<<i+1<<"]"<<"\t\t"<<bt[i]<<"\t\t"<<wt[i]<<"\t\t"<<tat[i];
}
avwt/=i;
avtat/=i;
cout<<"\n\nAverage Waiting Time:"<<avwt;
cout<<"\nAverage Turnaround Time:"<<avtat;
return 0;
}
OUTPUT:
EXPERIMENT-2
AIM: Write a program to illustrate Shortest Job First Scheduling
algorithm.
Program:
#include<iostream>
using namespace std;
int main(){
int bt[20],p[20],wt[20],tat[20],pr[20],i,j,n,total=0,pos,temp,avg_wt,avg_tat;
cout<<"Enter Total Number of Process:";
cin>>n;
cout<<"\nEnter Burst Time and Priority\n";
for(i=0;i<n;i++)
{
cout<<"\nP["<<i+1<<"]\n";
cout<<"Burst Time:";
cin>>bt[i];
cout<<"Priority:";
cin>>pr[i];
p[i]=i+1;
}
for(i=0;i<n;i++)
{
pos=i;
for(j=i+1;j<n;j++)
{
if(pr[j]<pr[pos])
pos=j;
}
temp=pr[i];
pr[i]=pr[pos];
pr[pos]=temp;
temp=bt[i];
bt[i]=bt[pos];
bt[pos]=temp;
temp=p[i];
p[i]=p[pos];
p[pos]=temp;
}
wt[0]=0;
for(i=1;i<n;i++)
{
wt[i]=0;
for(j=0;j<i;j++)
wt[i]+=bt[j];
total+=wt[i];
}
avg_wt=total/n;
total=0;
cout<<"\nProcess\t Burst Time
\tWaiting Time\tTurnaround Time";
}
for(i=0;i<n;i++)
{
tat[i]=bt[i]+wt[i];
total+=tat[i];
cout<<"\nP["<<p[i]<<"]\t\t "<<bt[i]<<"\t\t "<<wt[i]<<"\t\t\t"<<tat[i];
}
avg_tat=total/n;
cout<<"\n\nAverage Waiting Time="<<avg_wt;
cout<<"\nAverage Turnaround Time="<<avg_tat;
return 0;
OUTPUT:
EXPERIMENT-3
AIM: Write a program to illustrate Priority Scheduling algorithm.
Program:
#include<iostream>
using namespace std;
int main()
{
int bt[20],p[20],wt[20],tat[20],pr[20],i,j,n,total=0,pos,temp,avg_wt,avg_tat;
cout<<"Enter Total Number of Process:";
cin>>n;
cout<<"\nEnter Burst Time and Priority\n";
for(i=0;i<n;i++)
{
cout<<"\nP["<<i+1<<"]\n";
cout<<"Burst Time:";
cin>>bt[i];
cout<<"Priority:";
cin>>pr[i];
p[i]=i+1;
}
for(i=0;i<n;i++)
{
pos=i;
for(j=i+1;j<n;j++)
{
if(pr[j]<pr[pos])
pos=j;
}
temp=pr[i];
pr[i]=pr[pos];
pr[pos]=temp;
temp=bt[i];
bt[i]=bt[pos];
bt[pos]=temp;
temp=p[i];
p[i]=p[pos];
p[pos]=temp;
}
wt[0]=0;
for(i=1;i<n;i++)
{
wt[i]=0;
for(j=0;j<i;j++)
wt[i]+=bt[j];
total+=wt[i];
}
avg_wt=total/n;
total=0;
cout<<"\nProcess\t Burst Time \tWaiting Time\tTurnaround Time";
for(i=0;i<n;i++)
{
}
tat[i]=bt[i]+wt[i];
total+=tat[i];
cout<<"\nP["<<p[i]<<"]\t\t "<<bt[i]<<"\t\t
"<<wt[i]<<"\t\t\t"<<tat[i];
}
avg_tat=total/n;
cout<<"\n\nAverage Waiting Time="<<avg_wt;
cout<<"\nAverage Turnaround Time="<<avg_tat;
return 0;
OUTPUT:
EXPERIMENT-4
AIM: Write a program to illustrate Round Robin Scheduling
algorithm.
Program:
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
int wtime[10],btime[10],rtime[10],num,quantum,total;
cout<<"Enter number of processes(MAX 10): ";
cin>>num;
cout<<"Enter burst time";
for(int i=0;i<num;i++)
{ cout<<"\nP["<<i+1<<"]: ";
cin>>btime[i];
rtime[i] = btime[i];
wtime[i]=0;
}
cout<<"\n\nEnter quantum: "; cin>>quantum;
int rp = num;
int i=0;
int time=0;
cout<<"0"; wtime[0]=0; while(rp!=0) { if(rtime[i]>quantum)
{
rtime[i]=rtime[i]-quantum;
cout<<" | P["<<i+1<<"] | ";
time+=quantum;
cout<<time;
}
else if(rtime[i]<=quantum && rtime[i]>0)
{time+=rtime[i];
rtime[i]=rtime[i]-rtime[i];
cout<<" | P["<<i+1<<"] | ";
rp--;
cout<<time;
}
i++;
if(i==num)
{
i=0;
}
}
getch();
return 0;
}
OUTPUT:
EXPERIMENT-5
AIM: (a) Write a program to illustrate Least Recent Used Page
replacement algorithm.
Program:
#include <iostream>
using namespace std;
int min(int counter[],int nFrames)
{
int minimum = counter[0];
int pos = 0;
for(int i=0;i<nFrames;i++) { if(minimum > counter[i])
{ minimum = counter[i];
pos = i;
}
}
return pos;
}
int main()
{
int pageString[50],n,frames[10],counter[10],recent = 0;
int pageFault = 0,nFrames;
cout<<"Enter the number of pages: "; cin>>n;
cout<<"Enter the page reference string: ";
for(int i=0;i<n;i++) cin>>pageString[i];
cout<<"\nEnter the number of frames: "; cin>>nFrames;
for(int i=0;i<nFrames;i++)
{
frames[i] = 0;
counter[i] = 0;
}
for(int i=0;i<n;i++)
{ int flag =0;
for(int j=0;j<nFrames;j++)
{
if(frames[j] == pageString[i])
{flag=1;
counter[j] = recent++;
break;
}
}
if(flag == 0)
{
for(int j=0;j<nFrames;j++)
{if(frames[j] == 0)
{ frames[j] = pageString[i];
counter[j] = recent++;
flag=1;
pageFault++;
break;
}
}
}
if(flag == 0){
int PositionToreplace = min(counter,nFrames);
frames[PositionToreplace] = pageString[i];
counter[PositionToreplace] = recent++;
pageFault++;
}
cout<<endl;
for(int j=0;j<nFrames;j++)
{
cout<<frames[j]<<" ";
}
}
}
cout<<"\nPage Fault: "<<pageFault;
return 0;
OUTPUT:
AIM : (b) Write a program to illustrate First In First Out Page
replacement algorithm.
Program:
#include <iostream>
using namespace std;
int getReplaceposition(int counter[],int n)
{
int max = counter[0];
int pos=0;
for(int i=0;i<n;i++) { if(counter[i]>max)
{
pos=i;
max = counter[i];
}
}
return pos;
}
int main()
{
int pages[20],frames[10],counter[10];
int nPages,nFrames,pageFault=0;
cout<<"Enter the number of pages(MAX 20): ";
cin>>nPages;
cout<<"Enter the number of frames(MAX 10): ";
cin>>nFrames;
cout<<"Enter the Page reference string: ";
for(int i=0;i<nPages;i++){ cin>>pages[i];
}
for(int i=0;i<nFrames;i++)
{
frames[i] = 0;
counter[i] = 0;
}
for(int i=0;i<nPages;i++)
{int flag =0;
for(int j=0;j<nFrames;j++)
{
if(frames[j] == pages[i])
{flag=1;
break;
}
}
if(flag == 0)
{
pageFault++;
for(int j=0;j<nFrames;j++)
{
if(frames[j] == 0)
{ frames[j] = pages[i];
flag=1;
counter[j]++;
break;
}
}
}
}
if(flag == 0)
{
int pos = getReplaceposition(counter,nFrames);
frames[pos] = pages[i];
counter[pos] = 1;
for(int k=0;k<nFrames;k++)
{ if(k!=pos)
counter[k]++;
}
}
cout<<endl;
for(int j=0;j<nFrames;j++)
{
cout<<frames[j]<<" ";
}
}
cout<<"\nPage Fault: "<<pageFault;
return 0;
OUTPUT:
AIM: (c) Write a program to illustrate Optimal Page replacement
algorithm.
Program:
#include<iostream>
using namespace std;
#include<conio.h>
int main()
{
int nop,nof,page[20],i,count=0;
cout<<"\nEnter the No. of Pages:";
cin>>nop;
cout<<"\n Enter the Reference String:";
for(i=0;i<nop;i++)
{
cout<<"\t";
cin>>page[i];
}
cout<<"\n Enter the No of frames:-";
cin>>nof;
int frame[nof],fcount[nof];
for(i=0;i<nof;i++)
{
frame[i]=-1;
fcount[i]=0;
}
i=0;
while(i<nop)
{
int j=0,flag=0;
while(j<nof)
{
if(page[i]==frame[j]){
flag=1;
}
j++;
}
j=0;
cout<<"\n";
cout<<"\t"<<page[i]<<"-->";
if(flag==0)
{
if(i>=nof)
{
int max=0,k=0;
while(k<nof)
{
int dist=0,j1=i+1;
while(j1<nop)
{
if(frame[k]!=page[j1])
dist++;
else
{
break;
}
j1++;
}
fcount[k]=dist;
k++;
}
k=0;
while(k<nof-1)
{
if(fcount[max]<fcount[k+1])
max=k+1;
k++;
}
frame[max]=page[i];
}
else {
frame[i%nof]=page[i];
}
count++;
while(j<nof)
{
cout<<"\t|"<<frame[j]<<"|";
j++;
}
}
i++;
}
cout<<"\n";
cout<<"\n\tPage Fault is:"<<count;
getch();
return 0;
}
OUTPUT:
EXPERIMENT-6
AIM: Write a program to illustrate First Fit Memory Management.
Program:
#include<iostream>
#include<conio.h>
using namespace std;
int main(){
int num_blocks,num_files,blocks[10],files[10],fragment[10],filesAl[10];
int i=0,j=0;
for(i=0;i<10;i++)
{
fragment[i]=1;
filesAl[i]=0;
}
cout<<"\nEnter the No. of Blocks: ";cin>>num_blocks;
cout<<"\nEnter the No. of Files: ";cin>>num_files;
cout<<"\nEnter the sizes of blocks ";
for(i=0;i<num_blocks;i++)
{
cout<<"\nBlock["<<i+1<<"]: ";
cin>>blocks[i];
}
cout<<"\nEnter the sizes of files ";
for(i=0;i<num_files;i++)
{
cout<<"\nFile["<<i+1<<"]: ";
cin>>files[i];
}
for(i=0;i<num_files;i++)
{
for(j=0;j<num_blocks;j++)
{
if(files[i]<=blocks[j])
{
blocks[j]=blocks[j]-files[i];
if(blocks[j]!=0)
{
fragment[j]++;
}
filesAl[i]=1;
break;
}
}
}
cout<<"\nBLOCKS\tREMAIN\tFRAGMENTS";
for(i=0;i<num_blocks;i++)
cout<<endl<<i+1<<"\t"<<blocks[i]<<"\t"<<fragment[i];
cout<<"\n\nFiles which are not allcoated memory \n";
for(i=0;i<num_files;i++)
{
if(filesAl[i]==0)
{
cout<<"\nFile "<<i+1;
}
}
getch();
return 0;
}
OUTPUT:
EXPERIMENT-7
AIM: Write a program to illustrate Best Fit Memory Management.
Program:
#include <iostream>
using namespace std;
int main()
{
int nBlocks,nProcess,blockSize[20],processSize[20];
cout<<" Enter the number of blocks: ";
cin>>nBlocks;
cout<<" Enter the number of processes: ";
cin>>nProcess;
cout<<" Enter the size of "<<nBlocks<<" blocks: ";
for(int i=0;i<nBlocks;i++)
cin>>blockSize[i];
cout<<" Enter the size of "<<nProcess<<" processes: ";
for(int i=0;i<nProcess;i++)
cin>>processSize[i];
for(int i=0;i<nProcess;i++)
{
int min = 9999;
bool flag = false;
int pos=0;
for(int j=0;j<nBlocks;j++) {
if(min > blockSize[j] && processSize[i]<=blockSize[j])
{
min = blockSize[j];
flag = true;
pos = j;
}
}
if(flag)
{
blockSize[pos] = blockSize[pos] - processSize[i];
cout<<"\n\n Process "<<i+1<<" is allocated to Block "<<pos+1;
}
else
{
cout<<"\n\n Process "<<i+1<<" cannot be allocated";
}
cout<<"\n Remaining Block size\n";
for(int j=0;j<nBlocks;j++)
cout<<" "<<blockSize[j];
}
return 0;
}
OUTPUT:
EXPERIMENT-8
AIM: Write a program to illustrate Worst Fit Memory Management.
Program:
#include <iostream>
using namespace std;
int main()
{
int nBlocks,nProcess,blockSize[20],processSize[20];
cout<<" Enter the number of blocks: ";
cin>>nBlocks;
cout<<" Enter the number of processes: ";
cin>>nProcess;
cout<<" Enter the size of "<<nBlocks<<" blocks: ";
for(int i=0;i<nBlocks;i++) cin>>blockSize[i];
cout<<" Enter the size of "<<nProcess<<" processes: ";
for(int i=0;i<nProcess;i++) cin>>processSize[i];
for(int i=0;i<nProcess;i++)
{
int max = blockSize[0];
int pos = 0;
for(int j=0;j<nBlocks;j++)
if(max < blockSize[j]) { max = blockSize[j]; pos = j; }
if(max >= processSize[i])
{
cout<<"\nProcess "<<i+1<<" is allocated to block "<<pos+1;
blockSize[pos] = blockSize[pos]-processSize[i];
}
else{
cout<<"\nProcess "<<i+1<<" can't be allocated";
}
}
return 0;
}
OUTPUT: