priority.cpp

#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["<<p[i]<<"]\t\t "<<bt[i]<<"\t\t "<<wt[i]<<"\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;
}