However, it has the potential for procedure starvation for procedures which will necessitate a long time to complete if short procedures are continually added. While it is impossible to predict execution time perfectly, several methods can be used to estimate it, such as a weighted average of previous execution times.

COMING SOON!

```
"""
Shortest job remaining first
Please note arrival time and burst
Please use spaces to separate times entered.
"""
import pandas as pd
from typing import List
def calculate_waitingtime(
arrival_time: List[int], burst_time: List[int], no_of_processes: int
) -> List[int]:
"""
Calculate the waiting time of each processes
Return: list of waiting times.
>>> calculate_waitingtime([1,2,3,4],[3,3,5,1],4)
[0, 3, 5, 0]
>>> calculate_waitingtime([1,2,3],[2,5,1],3)
[0, 2, 0]
>>> calculate_waitingtime([2,3],[5,1],2)
[1, 0]
"""
remaining_time = [0] * no_of_processes
waiting_time = [0] * no_of_processes
# Copy the burst time into remaining_time[]
for i in range(no_of_processes):
remaining_time[i] = burst_time[i]
complete = 0
increment_time = 0
minm = 999999999
short = 0
check = False
# Process until all processes are completed
while complete != no_of_processes:
for j in range(no_of_processes):
if arrival_time[j] <= increment_time:
if remaining_time[j] > 0:
if remaining_time[j] < minm:
minm = remaining_time[j]
short = j
check = True
if not check:
increment_time += 1
continue
remaining_time[short] -= 1
minm = remaining_time[short]
if minm == 0:
minm = 999999999
if remaining_time[short] == 0:
complete += 1
check = False
# Find finish time of current process
finish_time = increment_time + 1
# Calculate waiting time
finar = finish_time - arrival_time[short]
waiting_time[short] = finar - burst_time[short]
if waiting_time[short] < 0:
waiting_time[short] = 0
# Increment time
increment_time += 1
return waiting_time
def calculate_turnaroundtime(
burst_time: List[int], no_of_processes: int, waiting_time: List[int]
) -> List[int]:
"""
Calculate the turn around time of each Processes
Return: list of turn around times.
>>> calculate_turnaroundtime([3,3,5,1], 4, [0,3,5,0])
[3, 6, 10, 1]
>>> calculate_turnaroundtime([3,3], 2, [0,3])
[3, 6]
>>> calculate_turnaroundtime([8,10,1], 3, [1,0,3])
[9, 10, 4]
"""
turn_around_time = [0] * no_of_processes
for i in range(no_of_processes):
turn_around_time[i] = burst_time[i] + waiting_time[i]
return turn_around_time
def calculate_average_times(
waiting_time: List[int], turn_around_time: List[int], no_of_processes: int
):
"""
This function calculates the average of the waiting & turnaround times
Prints: Average Waiting time & Average Turn Around Time
>>> calculate_average_times([0,3,5,0],[3,6,10,1],4)
Average waiting time = 2.00000
Average turn around time = 5.0
>>> calculate_average_times([2,3],[3,6],2)
Average waiting time = 2.50000
Average turn around time = 4.5
>>> calculate_average_times([10,4,3],[2,7,6],3)
Average waiting time = 5.66667
Average turn around time = 5.0
"""
total_waiting_time = 0
total_turn_around_time = 0
for i in range(no_of_processes):
total_waiting_time = total_waiting_time + waiting_time[i]
total_turn_around_time = total_turn_around_time + turn_around_time[i]
print("Average waiting time = %.5f" % (total_waiting_time / no_of_processes))
print("Average turn around time =", total_turn_around_time / no_of_processes)
if __name__ == "__main__":
print("Enter how many process you want to analyze")
no_of_processes = int(input())
burst_time = [0] * no_of_processes
arrival_time = [0] * no_of_processes
processes = list(range(1, no_of_processes + 1))
for i in range(no_of_processes):
print("Enter the arrival time and brust time for process:--" + str(i + 1))
arrival_time[i], burst_time[i] = map(int, input().split())
waiting_time = calculate_waitingtime(arrival_time, burst_time, no_of_processes)
bt = burst_time
n = no_of_processes
wt = waiting_time
turn_around_time = calculate_turnaroundtime(bt, n, wt)
calculate_average_times(waiting_time, turn_around_time, no_of_processes)
processes = list(range(1, no_of_processes + 1))
fcfs = pd.DataFrame(
list(zip(processes, burst_time, arrival_time, waiting_time, turn_around_time)),
columns=[
"Process",
"BurstTime",
"ArrivalTime",
"WaitingTime",
"TurnAroundTime",
],
)
# Printing the dataFrame
pd.set_option("display.max_rows", fcfs.shape[0] + 1)
print(fcfs)
```