fcfs.c

#include<stdio.h>
int main()
{   
    int at[10],at2[10],bt[100],ex[100],seq[100],re[100],wt[100],tat[100];
    int n,i,j,start,pos,max=0,min,idle=0,k=0;
    float av1=0,av2=0;

    printf("*****INPUT*****\n");
    printf("Enter number of process\n");
    scanf("%d",&n);
    printf("Enter arrival time for processess\n");
    for(i=0;i<n;i++)
    {
     scanf("%d",&at[i]);
     at2[i]=at[i];
    }
    printf("Enter burst time for processess\n");
    for(i=0;i<n;i++)
    {
     scanf("%d",&bt[i]);
    }
    start=at[0];
    for(i=1;i<n;i++)
    {
      if(start>at[i])
       {
       start=at[i];
       }
     }
    printf("*****OUTPUT*****\n");
    printf("Sequence of execution is\n");
    for(i=0;i<n;i++)
    {
    if(max<at[i])
     {
      max=at[i];
     }
    }
    max=max+1;
   for(i=0;i<n;i++,k++)
     {  min=max;
       for(j=0;j<n;j++){  
           if(at[j]!=-1)
             {
               if(at[j]<min)
                 {
                  min=at[j];
                  pos=j;
                 }
              }
         }
      printf("[P%d]  ",pos);
      seq[k]=pos;
      if(start<at[pos]){
         re[pos]=start;
         idle+=at[pos]-start;
         start=at[pos];
         start+=bt[pos];
         at[pos]=-1;
         ex[pos]=start;
      }
      else{
        re[pos]=start;
        start+=bt[pos];
        at[pos]=-1;
        ex[pos]=start;
       }
     }
    printf("\n");
    for(i=0;i<n;i++)
    {
       tat[i]=ex[i]-at2[i];
       wt[i]=tat[i]-bt[i];
    }
 printf("Process  Arrival-time(s)  Burst-time(s)  Waiting-time(s)  Turnaround-time(s)\n");
   for(i=0;i<n;i++)
    {
      printf("P%d            %d              %d             %d               %d\n",i,at2[i],bt[i],wt[i],tat[i]);
    }
   for(i=0;i<n;i++)
   {
    av1+=tat[i];
    av2+=wt[i];
   }
  printf("Average waiting time(s) %f\nAverage turnaroundtime(s) %f\nCPU idle time(s)%d\n",av2/n,av1/n,idle);
}