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javaalgorithmcpuschedulingdeadlines

Earliest deadline cpu scheduling


Updated: Solved my first question about sorting, but now I can't figure out how to show the correct diagram for the earliest deadline first algorithm with idle times.

Here is my code so far:

    import java.util.*;


    class deadlineprototype
    {


    public static void main(String args[])
    {


    Scanner sc = new Scanner(System.in);


    System.out.println("enter no. of processes : ");
    int n=sc.nextInt();
    int job[]=new int[n+1];
    int burst[]=new int[n+1];
    int newburst[]=new int[n+1];
    int arrival[]=new int[n+1];
    int deadline[]=new int[n+1];
    int wt[]=new int[n+1];
    int turn[]=new int[n+1];
    int tot_turn=0;
    int tot_wait=0;
    float avg_turn=0;
    float avg_wait=0;
    int j;

    for(int m=1;m<=n;m++)
        {
        arrival[m]=m;
        }
    for(int m=1;m<=n;m++)
        {
        job[m]=m;
        }

    for(int m=1;m<=n;m++)
        {
        System.out.println("enter arrival time, burst time and deadline of process "+(m)+"(0 for none):");
        arrival[m]=sc.nextInt();
        burst[m]=sc.nextInt();
        deadline[m]=sc.nextInt();
        
    if (deadline[m]==0){
        deadline[m]=1000;
    }
        }
        


    int temp;
    for(int i=0;i<n;i++)
{
   for(j=i;j<n;j++)
   {
      if(arrival[j+1] == arrival[j])
      { 
        if(deadline[j+1] < deadline[j])
        {
            temp=deadline[j+1];
            deadline[j+1]=deadline[j];
            deadline[j]=temp;

            temp=job[j+1];
            job[j+1]=job[j];
            job[j]=temp;

            temp=burst[j+1];
            burst[j+1]=burst[j];
            burst[j]=temp;


            temp=arrival[j+1];
            arrival[j+1]=arrival[j];
            arrival[j]=temp; 
        }
      }  
   }
}
    turn[1]=burst[1];    

    for(int i=2;i<=n;i++)
        {
        turn[i]=burst[i]+turn[i-1];
        wt[i]=turn[i]-burst[i];
        }
    for(int i=1;i<=n;i++)
        {
        tot_turn+=(wt[i]+burst[i])-arrival[i];
        avg_turn=(float)tot_turn/n;
        tot_wait+=wt[i]-arrival[i];
        avg_wait=(float)tot_wait/n;
        }
    System.out.println("----------Earliest Deadline Scheduling Diagram----------");
    for(int m=1;m<=n;m++)
        {
    if(deadline[m]==1000){
            deadline[m]=0;
            }
    if(wt[m]==0){
            System.out.println("0"+wt[m]+" _____"); 
    }
    else{
    System.out.println(wt[m]+" _____"); 
    }
            System.out.println("  |     |");
            
            System.out.println("  |job "+job[m]+"|");
            
            System.out.println("  |_____|");
                    try
                 {
                 //newburst[m]=(burst[m]*1000);
                 Thread.sleep(1000);  
                 }catch (InterruptedException ie)
                 {
                 System.out.println(ie.getMessage());
                 }
    }
    System.out.println((wt[wt.length-1]+burst[burst.length-1]));

If I input 2 processes without idle then it will show correct output:

enter no. of processes : 
2
enter arrival time, burst time and deadline of process 1(0 for none):
0 17 0
enter arrival time, burst time and deadline of process 2(0 for none):
0 13 10
----------Earliest Deadline Scheduling Diagram----------
00 _____
  |     |
  |job 2|
  |_____|
13 _____
  |     |
  |job 1|
  |_____|
30

But if it has idle time then it will output:

enter no. of processes(5-10): 
2
enter arrival time, burst time and deadline of process 1(0 for none):
0 5 0
enter arrival time, burst time and deadline of process 2(0 for none):
10 10 10
----------Earliest Deadline Scheduling Diagram----------
00 _____
  |     |
  |job 1|
  |_____|
5 _____
  |     |
  |job 2|
  |_____|
15

Solution

  • First sort the Processes based on the arrival time as follows,

        for(i=0;i<n;i++)
        {
           for(j=i;j<n;j++)
           {
              if(arrival[j+1] < arrival[j])
              {
                    temp=deadline[j+1];
                    deadline[j+1]=deadline[j];
                    deadline[j]=temp;
    
                    temp=job[j+1];
                    job[j+1]=job[j];
                    job[j]=temp;
    
                    temp=burst[j+1];
                    burst[j+1]=burst[j];
                    burst[j]=temp;
    
    
                    temp=arrival[j+1];
                    arrival[j+1]=arrival[j];
                    arrival[j]=temp; 
              }
           }
        }
    

    Afterwards if the arrival time of processes are equal sort them based on the deadline as follows,

        for(i=0;i<n;i++)
        {
           for(j=i;j<n;j++)
           {
              if(arrival[j+1] == arrival[j])
              { 
                if(deadline[j+1] < deadline[j])
                {
                    temp=deadline[j+1];
                    deadline[j+1]=deadline[j];
                    deadline[j]=temp;
    
                    temp=job[j+1];
                    job[j+1]=job[j];
                    job[j]=temp;
    
                    temp=burst[j+1];
                    burst[j+1]=burst[j];
                    burst[j]=temp;
    
    
                    temp=arrival[j+1];
                    arrival[j+1]=arrival[j];
                    arrival[j]=temp; 
                }
              }  
           }
        }