SJF and SRTF algorithm and program in c with gantt chart
Shortest Job first Scheduling Algorithm
1. Shortest Job First Scheduling Non Preemptive with Arrival time
Criteria: Brust time
Mode: Non Primitive
| Process No |
Arrival Time (AT) |
Brust time (BT)/ CPU Time |
Complication Time(CT) |
Turn Around Time(TAT) |
Waiting time(WT) |
Response Time(RT) |
| P1 |
1 |
3 |
6 |
5 |
2 |
2 |
| P2 |
2 |
4 |
10 |
8 |
4 |
4 |
| P3 |
1 |
2 |
3 |
2 |
0 |
0 |
| P4 |
4 |
4 |
14 |
10 |
6 |
6 |
Gantt Chart
0 1 3 6 10 14
Here,
Note: in empty house there have a black straight line
Turn Around Time(TAT) = Complication Time(CT) - Arrival Time (AT)
Waiting time(WT) = Turn Around Time(TAT) - Brust time (BT)
Response Time(RT) = When first come to the process in Gantt Chart - Arrival Time (AT)
2. Shortest Job First Scheduling Preemptive with Arrival time
Criteria: Brust time
Mode: Primitive
| Process No |
Arrival Time (AT) |
Brust time (BT)/ CPU Time |
Complication Time(CT) |
Turn Around Time(TAT) |
Waiting time(WT) |
Response Time(RT) |
| P1 |
2 |
6 |
20 |
18 |
12 |
12 |
| P2 |
1 |
3 |
4 |
3 |
0 |
0 |
| P3 |
4 |
2 |
6 |
2 |
0 |
0 |
| P4 |
0 |
5 |
10 |
10 |
5 |
0 |
| P5 |
6 |
4 |
14 |
8 |
4 |
4 |
Gantt Chart
| P4 |
P2 |
P2 |
P2 |
P3 |
P3 |
P4 |
P5 |
P1 |
0 1 2 3 4 5 6 10 14 20
Here,
Turn Around Time(TAT) = Complication Time(CT) - Arrival Time (AT)
Waiting time(WT) = Turn Around Time(TAT) - Brust time (BT)
Response Time(RT) = When first come to the process in Gantt Chart - Arrival Time (AT)
----------------------------x -------------------------
1. Shortest Job First Scheduling Non Preemptive with Arrival time in C programming language code
Here,
#include<iostream>
using namespace std;
int main()
{
int n, process[10],cpu[10],w[10],t[10],At[10],sum_w=0,sum_t=0,i,j,temp=0,temp1=0,temp2=0;
float avg_w, avg_t;
printf("enter the number of process\n");
scanf("%d", &n);
for(i=0; i<n; i++)
{
printf("Enter cpu time of P%d:",i+1);
scanf("%d", &cpu[i]);
printf("\n");
}
for(i=0; i<n; i++)
{
printf("Enter Arrival time time of P%d:",i+1);
scanf("%d", &At[i]);
printf("\n");
}
process[0]=1;
for(i=1; i<n; i++)
{
process[i]=i+1;
}
for(i=1; i<n; i++)
{
for(j=i+1; j<n; j++)
{
if(cpu[i]>cpu[j])
{
temp=cpu[i];
cpu[i]=cpu[j];
cpu[j]=temp;
temp1=process[i];
process[i]=process[j];
process[j]=temp1;
temp2=At[i];
At[i]=At[j];
At[j]=temp2;
}
}
}
w[0]=0-At[0];
for(i=1; i<n; i++)
{
w[i]=w[i-1]+cpu[i-1];
}
for(i=1; i<n; i++)
{
w[i]=w[i]-At[i];
sum_w=sum_w+w[i];
}
for(i=0; i<n; i++)
{
t[i]=w[i]+cpu[i];
sum_t=sum_t+t[i];
}
printf("Process--CPU_time--Wait--Turnaround\n");
for(i=0; i<n; i++)
{
printf(" P%d %d %d %d",process[i],cpu[i],w[i],t[i]);
printf("\n");
}
avg_w=(float)sum_w/n;
avg_t=(float)sum_t/n;
printf("average waiting time=%.2f\n",avg_w);
printf("average turnaround time=%.2f\n",avg_t);
cout<<"\n";
cout<<"===============================GrandChart====================================="<<endl<<"\n";
printf("|");
for(i=0; i<n; i++)
{
printf(" P%d |",process[i]);
}
printf("\n0");
for(i=0; i<n; i++)
{
printf(" %d",t[i]+At[i]);
}
}
2. Shortest Job First Scheduling Non Preemptive without Arrival time in C programming language code
Here,
#include<iostream>
#include<stdio.h>
using namespace std;
int main()
{
int n,
process[10],cpu[10],w[10],t[10],At[10],sum_w=0,sum_t=0,i,j,temp=0,temp1=0;
float avg_w, avg_t;
printf("enter the number of process\n");
scanf("%d", &n);
for(i=0; i<n; i++)
{
printf("Enter cpu time of P%d:",i+1);
scanf("%d", &cpu[i]);
printf("\n");
}
process[0]=1;
for(i=1; i<n; i++)
{
process[i]=i+1;
}
for(i=0; i<n; i++)
{
for(j=i+1; j<n; j++)
{
if(cpu[i]>cpu[j])
{
temp=cpu[i];
cpu[i]=cpu[j];
cpu[j]=temp;
temp1=process[i];
process[i]=process[j];
process[j]=temp1;
}
}
}
w[0]=0;
for(i=1; i<n; i++)
{
w[i]=w[i-1]+cpu[i-1];
}
for(i=0; i<n; i++)
{
sum_w=sum_w+w[i];
}
for(i=0; i<n; i++)
{
t[i]=w[i]+cpu[i];
sum_t=sum_t+t[i];
}
printf("Process--CPU_time--Wait--Turnaround\n");
for(i=0; i<n; i++)
{
printf(" P%d \t%d \t%d \t%d",process[i],cpu[i],w[i],t[i]);
printf("\n");
}
avg_w=(float)sum_w/n;
avg_t=(float)sum_t/n;
printf("average waiting time=%.2f\n",avg_w);
printf("average turnaround time=%.2f\n",avg_t);
cout<<"\n";
cout<<"===============================GrandChart====================================="<<endl<<"\n";
printf("|");
for(i=0; i<n; i++)
{
printf(" P%d |",process[i]);
}
printf("\n0");
for(i=0; i<n; i++)
{
printf(" %d",t[i]);
}
}
3. Shortest Job First Scheduling Preemptive with Arrival time in C programming language code
Here,
#include <iostream>
using namespace std;
int main(){
int i,j,k,p,s=0, get=0, idle=0, t_burst, t_row, pre_process_row, final=0;
float sum=0;
cout<<"Please enter the number process : ";
cin>>p;
int a[p][5];
int b[p][5];
cout<<"\nProcess\tArrival\tBurst\n-------\t-------\t-----\n";
for(i=0;i<p;i++){
for(j=0;j<3;j++){
cin>>a[i][j];
}
a[i][3]=a[i][2];
}
cout<<"\n\nTime-Line is as follows (Verticle View)....\n\n";
i=a[0][1];
while(final!=p){
get=0;
k=0;
while(k<p){
if(a[k][1]<=i){
if(a[k][2]!=0){
get=1;
t_burst=a[k][2];
t_row=k;
idle=0;
break;
}
else
k++;
}
else{
if(idle==0)
printf("%5d-----------\n |Idle |\n",i);
idle=1;
break;
}
}
if(get!=0){
k=0;
while(a[k][1]<=i && k<p){
if(a[k][2]!=0){
if(t_burst>a[k][2]){
t_burst=a[k][2];
t_row=k;
}
}
k++;
}
a[t_row][2]-=1;
if(i==a[0][1])
printf("%5d-----------\n |p-%-4d|\n",i,a[t_row][0]);
else{
if(pre_process_row!=t_row)
printf("%5d-----------\n |p-%-4d|\n",i,a[t_row][0]);
}
pre_process_row=t_row;
if(a[t_row][2]==0){
final++;
b[s][0]=a[t_row][0];
b[s][1]=a[t_row][1];
b[s][2]=i;
b[s][3]=a[t_row][3];
b[s][4]=((i-a[t_row][1])-a[t_row][3])+1;
sum+=((i-a[t_row][1])-a[t_row][3])+1;
s++;
}
}
i++;
}
printf("%5d-----------\n",i);
cout<<endl<<endl;
cout<<"Table of processes with completion record as they were completed\n\n";
cout<<"\n\nProcess\tArrival\tFin\tTotal\tWait\n-------\t-------\t---\t-----\t----\n";
for(i=0;i<s;i++)
cout<<b[i][0]<<"\t"<<b[i][1]<<"\t"<<b[i][2]<<"\t"<<b[i] [3]<<"\t"<<b[i][4]<<"\n";
cout<<"\nAvg. Wait time = "<<sum/p<<endl<<endl;
cout<<" \n\n";
return 0;
}
Thank You...
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