variables undefined while using pointers - c

Question

Hello i am slowly learning c and trying my best.
Can someone tell me why my variables are undefined?
"processId, userId, arrivalTime, priority, expectedTimeRemaining, expectedPctCPU, realTime" are all giving an error!
Please help, i provided my code. I tried reading up about structures and pointers. Followed resources, and now i am trying to implement it myself.
Thanks!
#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

You should use a linked list to store the data you need, here there is an example, this code reads the lines of a file named test.txt that has this layout:
100,101,20,1,50,1,0
102,105,30,1,55,1,1
101,10,40,0,56,1,1
and store all the values in a linked list, that contains your structure. I hope you'll learn something new, happy coding!
#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;
}