FCFS，python 3 我的代码有什么问题？

Question

我正在尝试“先到先得”的调度算法，但我所有的进程等待时间最终都为 0，即使其他等待时间看起来是正确的，或者至少取了一个不同于0.

如果有人对发生这种情况的原因有任何想法，请告诉我。

代码

class process:
    Pnum = 0
    burst = 0
    arrival = 0
    waitTime = 0
    turnAroundTime = 0
    responseTime = 0
    completionTime = 0
    first = False
    last = False
    def __init__(self,Pnum,burst,arrival):
        self.Pnum = Pnum
        self.burst = burst
        self.arrival = arrival

#  (Process#, Burst time, Arrival time)
P1 = process(1, 5, 0)
P2 = process(2, 2, 5)
P3 = process(3, 4, 10)
P4 = process(4, 2, 18)
P5 = process(5, 4, 20)

list = [P1,P2,P3,P4,P5]

P1.first = True
P5.last = True



def run(list):
    counter = 0
    for i in range(len(list)):
        #If this is the first process
        if i == 0: 
            list[i].completionTime = list[i].arrival + list[i].burst
        # If this process came before the previous process finished execution
        elif list[i].arrival < list[i-1].completionTime:
            list[i].completionTime = list[i-1].completionTime + list[i].burst
        # If there is a gap between this process adn the previous one
        else:
            list[i].completionTime = list[i].arrival + list[i].burst

        list[i].turnAroundTime = list[i].completionTime - list[i].arrival
        print(list[i].burst)
        list[i].waitTime = list[i].turnAroundTime - list[i].burst
        list[i].responseTime = list[i].waitTime 



run(list)

print("\n")
print("Process\t       Burst Time\tArrival\t        Complete\t Wait Time\t Turn Around Time\t")

for k in range(0,len(list)):
    print(str(list[k].Pnum)+"\t\t"+str(list[k].burst)+"\t\t"+
        str(list[k].arrival)+"\t\t"+str(list[k].completionTime)+"\t\t"+
        str(list[k].waitTime)+"\t\t"+str(list[k].turnAroundTime))

输出table：

Process        Burst Time   Arrival         Complete     Wait Time   Turn Around Time   
1                   5          0                5              0        5
2                   2          5                7              0        2
3                   4          10               14             0        4
4                   2          18               20             0        2
5                   4          20               24             0        4

Answer 1

原来代码是正确的，我以为进程在等待，但实际上不是。

Answer 2

我认为您的代码逻辑不正确，您“首先服务”那些具有最低 Pnum 的进程。顺便说一句，我认为惯例是你应该用小写字母命名变量。

FCFS，python 3 我的代码有什么问题？

FCFS, python 3 what's wrong with my code?

python

scheduled-tasks

代码

输出table：