c++ program of preemitive Shortest job first (SJF) scheduling algorithm.

#include<iostream.h>
#include<stdio.h>
int main()
{    int n=3;
    float total,wait[3]={0};
    float p[3],twaiting=0,waiting=0;
    int proc;
    int stack[3];
    float brust[3],arrival[3],sbrust,temp[3],top=3;
    for(int i=0;i<n;i++)
    {
        p[i]=i;
        stack[i]=i;
        cout<<"enter arival time :";
        cin>>arrival[i];
        cout<<endl<<"enter brust time:";
        cin>>brust[i];
        temp[i]=arrival[i];
        sbrust=brust[i]+sbrust;
    }   

  for(i=0;i<sbrust;i++)
    {
        proc=stack[0];
        if(temp[proc]==i)
                    twaiting=0;
        else
                  twaiting=i-(temp[proc]);
        temp[proc]=i+1;   
  
        wait[proc]=wait[proc]+twaiting;
        waiting=waiting+(twaiting);
         brust[proc]=brust[proc]-1;
   
            if(brust[proc]==0)
           {
            for(int x=0;x<top-1;x++)
                            stack[x]=stack[x+1];
            top=top-1;
           }
            for(int z=0;z<top-1;z++)
            {  
                 if((brust[stack[0]]>brust[stack[z+1]]) && (arrival[stack[z+1]] <= i+1))
              {
                       int t=stack[0];
            stack[0]=stack[z+1];
            stack[z+1]=t;
              }
          }
        }
  
cout<<"waiting:"<<waiting;
return 0;
}

Various Process Scheduling Algorithms:

• First come First served Scheduling Algorithm
• Non preemptive Shortest job first (SJF) scheduling Algorithm
• preemptive shortest job first (SJF) scheduling algorithm
• Non preemptive priority scheduling algorithm
• preemptive priority scheduling algorithm
• Roun Robin scheduling Algorithm

Various Page Replacement Algorithms:

• Page replacement using Least Recently Used (LRU) algorithm techneques.
• Page replacement using First come first served algorithm techniques.

Various Disk Head Movement Counting Algorithms:

• Count the disk head movement using first come first served (FCFS) algorithm
• head movement count using shortest seek job first (SSJF)
• head movement count using scan scheduling algorithm
• head movement count using c-scan scheduling algorithm
• head movement count using loop scheduling algorithm
• head movement count using c-loop scheduling alogrithm