Nsryjdtyk

How would I save different lines from a text File to different variables of different datatypes; all of these variables make up a struct (in my example a flight struct with the following).

struct Flight

{

     int flightNum;

     char desination[30];

     char departDay[15];

};

An Example of the information that I would like to add via text file would be.

111

NYC

Monday

I obviously want to save the words NYC and Monday to a char array, but I want to save 111 to an integer variable

So far I have

while (fscanf(flightInfo, "%s", tempName) != EOF)

{

     fscanf(flightInfo, "%dn", &tempNum);

     flight.flightNumber = tempNum;

     fscanf(flightInfo, "%sn", tempName);

     strcpy(flight.desination, tempName);

     fscanf(flightInfo, "%sn", tempName)

     strcpy(flight.departDay, tempName);

}

Assume that flightInfo is a pointer to a filename, tempNum is an integer, and tempName is a char array

It sounds like you're on the right track.

What about something like this:

#define MAX_FLIGHTS 100

...

struct Flight flights[MAX_FLIGHTS ];

int n_flights = 0;

...

while (!feof(fp) && (n_flights < MAX_FLIGHTS-1))

{

     if (fscanf(fp, "%dn", &flights[n_flights].flightNum) != 1)

        error_handler();

     if (fscanf(fp, "%29sn", flights[n_flights].destination) != 1)

        error_handler();

     if (fscanf(fp, "%14sn", flights[n_flights].departDay) != 1)

        error_handler();

     ++n_flights;

}

...

ADDENDUM:
Per Chux's suggestion, I've modified the code to mitigate against potential buffer overruns, by setting scanf max string length to 29 (1 less than char[30] buffer size).

Here is a more detailed explanation:

SonarSource: "scanf()" and "fscanf()" format strings should specify a field width for the "%s" string placeholder

The first question you have to answer is this: how important is it for the file to be readable by people, or on other platforms?

If it isn't that important, then I recommend serializing with fwrite() and fread(). That is easier to code for each record, and - as long as your structs are all the same size - allows O(1) access to any record in the file.

If you do want to store these as individual lines, the best way to read a line in from a file is with fgets()

Pseudocode follows:

typedef struct flight {

  int flightNum;

  char desination[30];

  char departDay[15];

} flight;



typedef struct flightSet {

  flight *flights;

  size_t n; /* number of flights */

  size_t nAlloc; /* number of flights you have space for */

} flightSet;



#define FLIGHTSET_INIT_SIZE 16

#define MAX_LINE_LENGTH 128

#define FILENAME "file.txt"



// Create a new flightSet, calling it F

// Allocate FLIGHTSET_INIT_ALLOC number of flight structures for F->flights

// Set F->n to 0

// Set F->nAlloc to FLIGHTSET_INIT_ALLOC



/* Set up other variables */

size_t i = 0;                       // iterator */

char buffer[MAX_LINE_LENGTH];   // for reading with fgets() */

flights *temp;                  // for realloc()ing when we have more flights to read

                            // after reaching nAlloc flights

char *endptr;                   // for using strtol() to get a number from buffer

FILE *fp;                       // for reading from the file



// Open FILENAME with fp for reading



//MAIN LOOP

  // If i == F->nAlloc, use realloc() to double the allocation of F->flights

  // If successful, double F->nAlloc



  if (fgets(buffer, MAX_LINE_LENGTH, fp) == NULL) {

      // End of file

      // Use break to get out of the main loop

  }



  F->flights[i]->flightNum = (int)strtol(buffer, &endptr, 10);

  if (endptr == buffer) {

    // The first invalid character that can't be converted to a number is at the very beginning

    // of the buffer, so this is not a valid numerical character and your data file is corrupt

    // Print out an error message

    break; 

  }



  if (fgets(buffer, MAX_LINE_LENGTH, fp) == NULL) {

      // End of file when expecting new line; file format error

      // Use break to get out of the main loop

  } else {

     F->flights[i]->destination = strdup(buffer);  // If your system has strdup()

     // Check for memory allocation

  }



  if (fgets(buffer, MAX_LINE_LENGTH, fp) == NULL) {

      // End of file when expecting new line; file format error

      // Use break to get out of the main loop

  } else {

     F->flights[i]->departDay = strdup(buffer);  // If your system has strdup()

     // Check for memory allocation

  }



  // If you've gotten here so far without errors, great!

  //    Increment F->n to reflect the number of successful records we have in F.

  //    Increment i, the loop iterator



//Final cleanup.  Should include closing the file, and freeing any allocated

//memory that didn't end up in a valid record.