OS-(I) Assignment 3: Set A- 1)

(1) Write the program to simulate FCFS CPU-scheduling. The arrival time and first CPU- burst for different n number of processes should be input to the algorithm. Assume that the fixed IO waiting time (2 units). The next CPU-burst should be generated randomly. The output should give Gantt chart, turnaround time and waiting time for each process. Also find the average waiting time and turnaround time.

Solution:

#include<stdio.h>

int findWaitingTime(int bt[],int wt[],int n)

{

    int wtavg=0,i;

    wt[0]=0;

    for(i=1;i<n;i++)

    {

       wt[i]=bt[i-1]+wt[i-1]+2;

       wtavg=wtavg+wt[i];

    }

    return(wtavg);

}

int findTurnAroundTime(int bt[],int wt[],int tat[],int n)

{

    int tatavg=0,i;

    for (i=0;i<n;i++)

    {

       tat[i]=bt[i]+wt[i];

       tatavg=tatavg+tat[i];

    }

    return(tatavg);

}

void main()

{

   int at[10],bt[10],wt[10],tat[10],i,n;

   int avgwt,avgtat;

   printf("\nEnter the number of process\n");

   scanf("%d",&n);

   for(i=0;i<n;i++)

   {

      bt[i]=rand()%10;

   }

  for(i=0;i<n;i++)

  {

     printf("%d\t",bt[i]);

  } 

   avgwt=findWaitingTime(bt,wt,n)/n;

   avgtat=findTurnAroundTime(bt,wt,tat,n)/n;

   printf("\n\nP|\tBT\tWT\tTAT|\n");

   for(i=0;i<n;i++)

   {

      printf("%d",i);

      printf("\t%d",bt[i]);

      printf("\t%d",wt[i]);

      printf("\t%d\n",tat[i]);

   }

   printf("\nGantt Chart\n");

   for(i=0;i<n;i++)

   {

       printf("|   P%d\t",i);

   }

   printf("|\n");

   for(i=0;i<n;i++)

   {

      printf("%d\t ",wt[i]);

   }

   printf("%d\n",tat[i-1]);

   printf("Average Waiting Time=%d",avgwt);

   printf("\n");

   printf("Average Turn Around Time=%d",avgtat);

}