I am working on an assignment where I am to read an input file (input.txt) like

Question

I am working on an assignment where I am to read an input file (input.txt) like so:

We are given the PCB structure: struct PCB {int ProcId; int ProcPR, int CPUburst; int Reg[8]; int queueEnterClock, waitingTime; /* other info */ struct PCB *next;}

and a CPU to be written as int CPUreg[8] = {0};;

Given linked list variables: struct PCB *Head=NULL; struct PCB *Tail=NULL;

Other variables: int CLOCK=0; int Total_waiting_time=0; int Total_turnaround_time=0; int Total_job=0.

That was what given, my question is how do I go about doing the following task:

For each input line, read a line consisting of three integers: Process Id, Process Priority, CPU Burst time. (The values in the input.txt from left to right)

Dynamically create a struct PCB pointed by PCB, save the given data into correponding fields of PCB, set all PCB->Reg[8] to the Process ID, set PCB->queueEnterClock and PCB->waitingTime to 0, then insert this PCB at the end of the link list.

Explanation / Answer

FILE* file = fopen("filename", "r");
if (file){
int ProcId, ProcPR, CPUburst;
// Read line by line till file end
while (fscanf(file, "%d %d %d", &ProcId, &ProcPR, &CPUburst) != EOF){
    // Dynamically allocate memory for list node
    struct PCB *node = (PCB*)malloc(sizeof(PCB));
    node->ProcId = ProcId;
    node->ProcPR = ProcPR;
    node->CPUburst = CPUburst;
    node->queueEnterClock = 0;
    node->waitingTime = 0;
    for(int i=0; i<8; i++){
      node->Reg[i] = ProcId;
    }
    node->next = NULL;
    // Insert node at end of linked list
    if (Head == NULL){
      Head = node;
      Tail = node;
    } else {
      Tail->next = node;
      Tail = node;
    }
}
}

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