8.Write program to implement SJF scheduling algorithm (Non-Preemptive)

Write program to implement SJF scheduling algorithm (Non-Preemptive)

//cskecode

#include<iostream>

#include<stdio.h>
using namespace std;
class sjf
{      
public:
int burst_tm,arv_tm,wait_tm,temp;
char pid;
sjf()
{
temp=0;
//status=0;
}
};
int main()
{
int n,sum=0,carry=0;
float avg_wait_tm=0,avg_around_tm=0;
cout<<"Enter the no. of processes:\n";
cin>>n;
sjf temp;
sjf *f=new sjf[n];
for( int i=0;i<n;i++)
{
cout<<"Enter the process id:\n";
cin>>f[i].pid;
cout<<"Enter the burst timing:\n";
cin>>f[i].burst_tm;
cout<<"Enter the arrival timing:\n";
cin>>f[i].arv_tm;
}
   
int k1=0,flag=1;
while(k1<n)
{
if(f[k1].arv_tm==0)
{
flag=0;
break;
}
k1++;
}
if(flag==1)
{
cout<<"enter all values of arival time as no arrival time is 0\n";
return 1;
}
   
for(int k=0;k<n;k++)
{
temp=f[k];
for(int i=k+1;i<n;i++)
{
if(temp.arv_tm>f[i].arv_tm)
{
temp=f[i];
f[i]=f[k];
f[k]=temp;
}
//cout<<"f[0]: "<<f[0].pid<<endl;
}
}
   
for(int k=0;k<n;k++)
{
cout<<"pid: "<<f[k].pid<<endl<<"Burst time: "<<f[k].burst_tm<<endl<<"arrival time: "<<f[k].arv_tm<<endl<<"Waiting time: "<<f[k].wait_tm<<endl;
                   
}
   
cout<<"Entered info is as follows:\n";
carry=f[0].arv_tm;
int i=0;
for(int k=1;k<n;k++)
{
if(f[k].arv_tm==carry)
{
if(f[i].burst_tm>f[k].burst_tm)
i=k;
}
else
{
cout<<"carry break\n";
break;
}
}
   
int j,tem=0,k,b;
do
{
j=0;
if((f[i].arv_tm<=sum)&&(f[i].temp!=1))
{
f[i].wait_tm=sum-f[i].arv_tm;
f[i].temp=1;
sum+=f[i].burst_tm;
}
else
{
if(tem==0)
{
sum=f[i].arv_tm;
tem=1;
}
f[i].wait_tm=sum-f[i].arv_tm;
f[i].temp=1;
sum+=f[i].burst_tm;
}
flag=1;
for(int k=0;k<n;k++)
{
if(f[k].arv_tm<=sum)
{
 //flag=0;
if(f[k].temp==1)
j++;
else if((f[k].burst_tm<f[i].burst_tm)||(f[i].temp==1))
{
flag=0;
i=k;
}
}
}
                                   
if((flag==1)&&(j!=n-1))
{
for(b=i;b<n;b++)
if(!f[b].temp)
{
carry=f[b].arv_tm;
i=b;
break;
}
for(int t=b+1;t<n;t++)
{
if(f[t].arv_tm==carry)
{
if(f[t].burst_tm<f[i].burst_tm)
i=t;
}
else
break;
}
}
}while(j!=n);
                                                                                                   
                                             
for(k=0;k<n;k++)
{
cout<<"pid: "<<f[k].pid<<endl<<"Burst time: "<<f[k].burst_tm<<endl<<"arrival time: "<<f[k].arv_tm<<endl<<"Waiting time: "<<f[k].wait_tm<<endl;
avg_wait_tm+=f[k].wait_tm;
avg_around_tm+=f[k].wait_tm+f[k].burst_tm;
                   
                   
}
avg_around_tm/=n;
avg_wait_tm/=n;
cout<<"average turn around time:\n"<<avg_around_tm<<endl<<"average waiting time:\n"<<avg_wait_tm<<endl;
   
//cout<<"average turn around time:\n"<<avg_around_tm<<endl<<"average waiting time:\n"<<avg_wait_tm<<endl;
getchar();
getchar();
getchar();
   
return 0;
}

Output: