Short Job First Non PREEMPTIVE with arrival time CPU Scheduling Algorithm in C Source code program

 #include <stdio.h>  
 #include <conio.h>  
 /* Short Job First NON PREEMPTIVE CPU Scheduling Algorithm  
   By Suraj Jha & Abhas Tandon  
   Please note that program has some extra printf statements that were used for debugging   
   They can be removed if required  
 */  
 int n;  
 struct sjf{  
     int sr;  
     int wt,bt,at,tat;  
     int flag;  
     }arr[10];  
 struct sjf queue[15];  
 int f=-1,r=-1;  
 void enqueue(struct sjf x){  
    if(f==-1 && r==-1)  
    {  
     queue[++f]=x;  
     r++;      
    }  
    else{  
     queue[++r]=x;     
    }  
    printf("Added %d to queue\n",queue[r].sr);  
 }  
 int dequeue(){  
    int x=f;  
    if(f==r)  
        f=r=-1;    
    else  
      f++;  
    printf("Dequeue %d\n",queue[x].sr);  
    return queue[x].sr;  
 }  
 void sortQueue(){  
    int i,j;  
    for(i=f;i<=r;i++)  
    {  
     for(j=i+1;j<=r;j++) {  
      if(queue[i].bt>queue[j].bt)  
      {  
       struct sjf temp= queue[i];  
       queue[i]=queue[j];  
       queue[j]=temp;               
      }           
     }         
    }  
 }  
 void dispq(){  
    int i;  
    if(f==-1)  
    printf("Empty");  
    for(i=f;i<=r;i++)  
    printf("%d ",queue[i].sr);  
    printf("\n%d %d\n",f,r);     
 }  
 float awt,atat;  
 void input(){  
        printf("Enter Number of processes:");  
        scanf("%d",&n);  
        int i;  
        for(i=0;i<n;i++)  
        {  
          printf("Enter Burst Time of process %d:",i+1);  
          scanf("%d",&arr[i].bt);         
          printf("Enter Arrival Time of process %d:",i+1);  
          scanf("%d",&arr[i].at);   
          arr[i].sr=i;   
          arr[i].flag=0;         
        }  
 }  
 void calculate(){  
    int i,j,btto;  
    arr[0].wt=0;  
    //arr[0].flag=1;  
    int btt=arr[0].bt;  
    arr[0].tat=arr[0].bt;  
    atat=arr[0].bt;  
    i=0;  
    do{  
      printf("Start of Do While\n");  
      for(j=1;j<n;j++){  
        printf("cmp arr[j] %d btt %d jFlag %d\n",arr[j].at,btt,arr[j].flag);  
        if(arr[j].at<btt )  
        enqueue(arr[j]);        
      }   
      sortQueue();  
      printf("Sorted Queue\n");  
      btto=btt;//Starting time for this process  
      printf("Btto=%d\n",btto);  
      int pid=dequeue();  
      while(arr[pid].flag==1){  
      pid=dequeue();              
      }  
      btt+=arr[pid].bt;  
      printf("After Adding %d btt =%d\n",queue[f].bt,btt);  
      arr[pid].flag=1;//to show that process is executed  
      printf("%d Process %d executed",i,pid);  
      arr[pid].wt=btto - arr[pid].at;  
      arr[pid].tat= arr[pid].bt+ arr[pid].wt;      
      printf("A %d %d %d %d\n",btto,arr[pid].at,arr[pid].bt,arr[pid].wt);   
      awt+=arr[pid].wt;  
      atat+= arr[pid].tat;   
      //printf("%d %d\n",f,r);   
      i++;      
      printf("I incremented\n");  
      dispq();   
      while(f!=-1)  
      dequeue();  
      printf("Queue refresed Ready for next run\n");  
    }while(i<n-1);  
    awt/=n;  
    atat/=n;  
 }  
 void display(){  
    int i;  
    printf("SR.\tA.T.\tB.T.\tW.T.\tT.A.T.\n");  
    for(i=0;i<n;i++)  
    {  
    printf("%3d\t%3d\t%3d\t%3d\t%4d\n",i+1,arr[i].at,arr[i].bt,arr[i].wt,arr[i].tat);          
    }    
    printf("Average Waiting Time: %f\nAverage Turn Around Time:%f",awt,atat);  
 }    
 int main(){  
       printf("SJF CPU Scheduling Algorithm\n");  
       input();  
       calculate();  
       display();   
       getch();   
 }