Program:1
AIM : Write a program to implement First Come First Scheduling(FCFS).
Code :
#include<iostream>
using namespace std;
int main()
{ int n,bt[20],wt[20],tat[20],avg_wt=0,avg_tat=0,i,j;
cout<<"Enter total number of processes:";
cin>>n;
cout<<"\nEnter Process Burst Time DURATION \n";
for(i=0;i<n;i++)
cout<<"P["<<i+1<<"]:";
cin>>bt[i];
wt[0]=0; //waiting time for first process is 0
//calculating waiting time
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\tTurn
around Time";
//calculating turnaround time
for(i=0;i<n;i++)
tat[i]=bt[i]+wt[i];
avg_wt+=wt[i];
avg_tat+=tat[i];
cout<<"\nP["<<i+1<<"]"<<"\t\t\t"<<bt[i]<<"\t\t\t\t"<<wt[i
]<<"\t\t\t\t"<<tat[i];
avg_wt/=i;
avg_tat/=i;
cout<<"\n\nAverage Waiting Time:"<<avg_wt;
cout<<"\nAverage Turnaround Time:"<<avg_tat;
return 0;
}
Program:2
AIM : Write a program to implement Shortest Job First scheduling(SJF).
Code:
#include <iostream>
using namespace std;
int main()
int A[100][4];
int i, j, n, total = 0, index, temp;
float avg_wt, avg_tat;
cout << "Enter number of process: ";
cin >> n;
cout << "Enter Burst Time:" << endl;
// User Input Burst Time and alloting Process Id.
for (i = 0; i < n; i++) {
cout << "P" << i + 1 << ": ";
cin >> A[i][1];
A[i][0] = i + 1;
// Sorting process according to their Burst Time.
for (i = 0; i < n; i++) {
index = i;
for (j = i + 1; j < n; j++)
if (A[j][1] < A[index][1])
index = j;
temp = A[i][1];
A[i][1] = A[index][1];
A[index][1] = temp;
temp = A[i][0];
A[i][0] = A[index][0];
A[index][0] = temp;
A[0][2] = 0;
// Calculation of Waiting Times
for (i = 1; i < n; i++) {
A[i][2] = 0;
for (j = 0; j < i; j++)
A[i][2] += A[j][1];
total += A[i][2];
avg_wt = (float)total / n;
total = 0;
cout << "P BT WT TAT" << endl;
// Calculation of Turn Around Time and printing the
// data.
for (i = 0; i < n; i++) {
A[i][3] = A[i][1] + A[i][2];
total += A[i][3];
cout << "P" << A[i][0] << " " << A[i][1] << "
" << A[i][2] << " " << A[i][3] << endl;
avg_tat = (float)total / n;
cout << "Average Waiting Time= " << avg_wt << endl;
cout << "Average Turnaround Time= " << avg_tat <<
endl;
}
Program:3
AIM : Write a program to implement priority based scheduling.
Code :
#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; //contains process number
//sorting burst time, priority and process number in
ascending order using selection sort
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; //waiting time for first process
is zero
//calculate waiting time
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; //average waiting time
total=0;
cout<<"\nProcess\t Burst Time \tWaiting
Time\tTurnaround Time";
for(i=0;i<n;i++)
tat[i]=bt[i]+wt[i]; //calculate turnaround time
total+=tat[i];
cout<<"\nP["<<i+1<<"]"<<"\t\t\t"<<bt[i]<<"\t\t\t\t"<<wt[i
]<<"\t\t\t\t"<<tat[i];
avg_tat=total/n; //average turnaround time
cout<<"\n\nAverage Waiting Time="<<avg_wt;
cout<<"\nAverage Turnaround Time="<<avg_tat;
return 0;
