Answer to Question #271820 in C for Jim

Question

Write a program to implement round robin scheduling concept using a linked list. Each node will represent a process with attributes as <PID, CPU_time>. A quantum time T will be input by the user.

A process will be executed (when user wants) for quantum time T and the CPU_time will be updated with CPU_time T, and the current process node is deleted from the beginning and added to the end of the list. If the updated CPU_time is <=0, then the process is deleted from the list.

After a process is executed for T time, the the next process in the queue is executed upon user choice. The entire process gets completed when all process nodes are deleted.

Answer 1

#include<stdio.h>
#include<stdbool.h>
void findWaitingTime(int process[], int n,
            int Cpu_time[], int PID[], int Q)
{
    int rem_Q[n];
    for (int i = 0 ; i < n ; i++)
        rem_Q[i] = Cpu_time[i];
 
    int t = 0;
    while (1)
    {
        bool done = true;
        for (int i = 0 ; i < n; i++)
        {
            if (rem_Q[i] > 0)
            {
                done = false; 
 
                if (rem_Q[i] > Q)
                {
                    t += Q;
                    rem_Q[i] -= Q;
                }
                else
                {
                    t = t + rem_Q[i];
                    PID[i] = t - Cpu_time[i];
                    rem_Q[i] = 0;
                }
            }
        }
        if (done == true)
        break;
    }
}
void findTurnAroundTime(int process[], int n,
                        int Cpu_time[], int PID[], int tat[])
{
    for (int i = 0; i < n ; i++)
        tat[i] = Cpu_time[i] + PID[i];
}
void findavgTime(int process[], int n, int Cpu_time[],
                                    int Q)
{
    int PID[n], tat[n], total_wt = 0, total_tat = 0;
    findWaitingTime(process, n, Cpu_time, PID, Q);
    findTurnAroundTime(process, n, Cpu_time, PID, tat);
    printf("Processes ");
    printf(" Burst time ");
    printf(" Waiting time " );
    printf(" Turn around time\n");
    for (int i=0; i<n; i++)
    {
        total_wt = total_wt + PID[i];
        total_tat = total_tat + tat[i];
        printf(" " );
        printf("%d",i+1);
        printf("\t\t" );
        printf("%d",Cpu_time[i] );
        printf("\t ");
        printf("%d",PID[i] );
        printf("\t\t " );
        printf("%d",tat[i] );
        printf("\n");
    }
 
    printf("Average waiting time = ");
    printf("%lf",(float)total_wt / (float)n);
    printf("\nAverage turn around time = ");
    printf("%lf",(float)total_tat / (float)n);
}
int main()
{
    int process[] = { 1, 2, 3};
    int n = sizeof process / sizeof process[0];
    int BTime[] = {10, 5, 8};
    int Q = 2;
    findavgTime(process, n, BTime, Q);
    return 0;
}