ShortestJobFirstScheduling.c

#include <stdio.h>

// Structure to represent a process
typedef struct
{
  int name; // Process name (1, 2, 3, ...)
  int AT;   // Arrival time
  int BT;   // Burst time
  int CT;   // Completion time
  int WT;   // waiting time
  int TAT;  // turn around time

} Process;

void sortAT(Process processes[], int n)
{
  Process temp;
  for (int i = 0; i < n - 1; i++)
  {
    for (int j = i + 1; j < n; j++)
    {
      if (processes[i].AT > processes[j].AT)
      {
        temp = processes[i];
        processes[i] = processes[j];
        processes[j] = temp;
      }
    }
    processes[i].CT = 0;
  }
}

int main()
{
  // Define the processes
  Process processes[] = {
      {2, 5, 2}, // Arrival time = 1, Burst time = 1
      {4, 0, 3}, // Arrival time = 3, Burst time = 2
      {5, 4, 4}, // Arrival time = 4, Burst time = 6
      {3, 1, 8}, // Arrival time = 2, Burst time = 3
      {1, 2, 6}, // Arrival time = 0, Burst time = 8
  };
  int n = sizeof(processes) / sizeof(Process); // Number of processes

  sortAT(processes, n);
  
  int currenttime = 0;
  int completedProcess = 0;
  Process temp=processes[0];

  while(completedProcess<n){
    for (int i = 0; i < n; i++)
    {
      if(processes[i].AT<=currenttime && processes[i].CT==0 ){
        if(processes[i].BT<temp.BT){
          temp = processes[i];
        }
      }
    }
    int execution_time = temp.BT;

    currenttime += execution_time;
    temp.CT = currenttime;
    temp.TAT = temp.CT - temp.AT;
    temp.WT = temp.TAT - temp.BT;
    completedProcess++;
    for (int i = 0; i < n; i++)
    {
      if (processes[i].name == temp.name)
      {
        processes[i] = temp;
        temp.BT=9999;
        break;
      }
    }
}

float avgWt = 0.0;
float avgTat = 0.0;
printf("Process  ArrivalTime BurstTime CompletedTime TurnaroundTime    WaitingTime\n");
for (int i = 0; i < n; i++)
{
  printf("P%d%10d%15d%10d%15d%20d\n", processes[i].name, processes[i].AT, processes[i].BT, processes[i].CT, processes[i].TAT, processes[i].WT);
  avgWt = avgWt + processes[i].WT;
  avgTat = avgTat + processes[i].TAT;
}
printf("Average Waiting Time=%f\n", avgWt / n);
printf("Average turnaround Time=%f\n", avgTat / n);

return 0;
}