How do I work out the AWT and TAT in my code ?

I am having problems calculating the average turn around time and average waiting time in my program. Can anyone give me some advice where i am going wrong please? :( :confused: I am first trying to work out the turn around time and then the waiting time so that i can use qaunta to subract away from the TAT.

Code:

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/* Process each priority */
for ( sb = 0, nsb = 0, priority = 0; priority < PRIORITIES; priority++ )
{
        sb = nsb;
       
        printf("Starting priority %d. \n", priority );
       
        /* process this priority level */
        for ( fp = 1, qsum = 0, ntp = 0, pcur = 0; ; pcur++)
        {
                /* If we have gone too far */
                if ( sb + pcur == num_procs || pq[ sb + pcur ].priority > priority )
                {
                        if (fp ) /* Is this the first pass? */
                        {
                        nsb = sb + pcur; /* Keep the nsb in the same priority group */
                        fp = 0;
                        ntp += qsum;
                       
                        printf("Priority %d, qsum %d\n", priority, qsum);
                        }
                        pcur = 0; /* Reset the bucket */
                       
                        if ( ntp == 0 ) /* Do we have any that we need to process? */
                        {
                        printf( "Priority %d finished. \n\n", priority);
                        break;
                        }
                }

                /* if we have a quantum to process */
                if ( pq [sb + pcur ].quantum > 0 )
                {
                        if ( fp ) /* On the first pass, sum bucket values */
                        {
                        qsum += pq [ sb + pcur ].quantum;
                        pq[ sb + pcur ].started = timer; // make note when process starts
                        printf("%s started at %d\n", pq[ sb + pcur ].id, pq[ sb + pcur].started);
                        }
                       
                        ntp--;
                        printf("%s %d %d\t pq [ %d ]\t ntp: %d\n",pq[ sb + pcur ].id, pq[ sb + pcur].quantum, priority,  sb + pcur, ntp);
                        pq[sb + pcur ].quantum--;
                        timer++;
                       
                        /* If process ended, make note of when it ended */
                        if ( pq [sb + pcur ].quantum == 0 )
                        {
                        pq[sb + pcur].finished = timer; // make note when the process ends
                        tat = pq[sb + pcur].finished - pq[sb + pcur].started;
                        atat += tat; // add all tat times together to work out average
                        printf("%s finished at %d tat of %f\n", pq[sb + pcur].id, pq[sb + pcur].finished, tat);
                        }       
                }
        }
       
}

printf("All Process have completed\n");
printf("Average Turn Around Time: %f \n", atat / num_procs);

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