c - 使用指针时变量未定义

Question

你好，我正在慢慢学习c并尽力而为。有人能告诉我为什么我的变量未定义吗？“processId、userId、arrivalTime、priority、expectedTimeRemaining、expectedPctCPU、realTime”都给出错误!

请帮忙，我提供了我的代码。我尝试阅读有关结构和指针的内容。遵循资源，现在我正在尝试自己实现。谢谢!

#include <stdio.h>
#include <stdlib.h> 
#include <string.h> 
#include <ctype.h>
#include <stdbool.h>
#define _CRT_SECURE_NO_WARNINGS

typedef enum States { NEW, READY, RUNNING, BLOCKED, SUSPENDED, EXIT, SUSPEND_READY } State;
char stateNames[7][14] = { "New", "Ready", "Running", "Blocked", "Suspended", "Exit", "SuspendReady" };


// partial - skips info needed to actually conduct process switch - contents of registers, program counter, stack pointers, ... pointers to page tables ...
// we ARE going to need some way of indicating IO needs so can decide when they should block
struct processblock {
    int processId;
    int userId;         // pointer instead?
    State processState; // Not input - initially NEW
    int arrivalTime;   // time units in simulation, not actual time
    int priority;          // base priority
    int currentPriority;   // can be upped or lowered based on what has happened with the process - not input - initially same as base priority
    int timeWaitingSoFar;   // Not input - initially zero
    int timeProcessingLastRun; // Not input - initially zero
    int timeProcessingSoFar; // Not input - initially zero
    int expectedTimeRemaining;
    struct event* waitingOn;   // ??? // Not input - initially zero
    int expectedMemoryNeed;
    int expectedPctCPU;     // to get an idea of whether CPU bound or IO bound
    bool realTime;          // whether a real-time process or not (real-time processes may need immediate attention)
    struct processblock* nextPtr; // not used in this program - but preparing for linked list version
};

//fill in the array from file
int fillArrayFromFile(struct processblock processor[], FILE*fPtr, int maxSize) {
    int count = 0;
    //unsure if realtime is a parameter, pls check and confirm with me
    while ((count < maxSize) && fscanf("fPtr,%d,%d,%d,%d,%d,%d,%d", processId, userId, arrivalTime, priority, expectedTimeRemaining, expectedPctCPU, realTime) != EOF) {
        //fill in each part of the array
        processor[count].processId = count;
    }
}

Answer 1

您应该使用链接列表来存储您需要的数据，这里有一个示例，此代码读取具有以下布局的名为 test.txt 的文件中的行:

100,101,20,1,50,1,0

102,105,30,1,55,1,1

101,10,40,0,56,1,1

并将所有值存储在包含您的结构的链接列表中。我希望您能学到一些新的东西，快乐地编码!

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#define _CRT_SECURE_NO_WARNINGS

typedef enum States { NEW, READY, RUNNING, BLOCKED, SUSPENDED, EXIT, SUSPEND_READY } State;

char * stateNames[7] = { "New", "Ready", "Running", "Blocked", "Suspended", "Exit", "SuspendReady" };


struct processblock {
    int processId;
    int userId;
    int arrivalTime;
    int priority;
    int expectedTimeRemaining;
    int expectedPctCPU;
    int realTime;          // scanf can't read boolean


    State processState;
    int currentPriority;
    int timeWaitingSoFar;
    int timeProcessingLastRun;
    int timeProcessingSoFar;
    int expectedMemoryNeed;
};

struct Node
{
  struct processblock pblock;
  struct Node *next;
};

typedef struct Node * List;

void NewNode(List * p , struct processblock pb) //function that creates new linked list nodes
{
    List temp;

    temp = (List)malloc(sizeof(struct Node));
    temp->pblock = pb;
    temp->next = *p;

    *p = temp;
}

int fillArrayFromFile(char *filename, List * p) {

  FILE *fPtr;
  int count = 0;
  struct processblock pb;
  char * buffer;
  buffer = malloc(sizeof(struct processblock));

  if(!(fPtr= fopen(filename, "r")))
  {
    perror("No File");
    fclose(fPtr);
    return 0;
  }

  while(fgets(buffer,sizeof(struct processblock),fPtr))//read every line of file and store them in a buffer
      {
        if(sscanf(buffer,"%d,%d,%d,%d,%d,%d,%d", &pb.processId, &pb.userId, &pb.arrivalTime, &pb.priority, &pb.expectedTimeRemaining, &pb.expectedPctCPU, &pb.realTime) == 7 ) // read from the buffer
        {
          NewNode(p, pb); // creates new node from filled structure
          count++;
        }
      }
  free(buffer);
  fclose(fPtr);
  return count;
}

void ViewElements(List p)
{
  struct processblock pb;
  while(p != NULL)
  {
    pb = p->pblock;
    printf("%d,%d,%d,%d,%d,%d,%d\n", pb.processId, pb.userId, pb.arrivalTime, pb.priority, pb.expectedTimeRemaining, pb.expectedPctCPU, pb.realTime);
    p = p->next;
  }

}
int main()
{
  List HeadNode = NULL;

  printf("Loaded %d lines\n", fillArrayFromFile("test.txt", &HeadNode));
  ViewElements(HeadNode);
  return 0;
}