CODEWITHSUNDEEP
cstrtok
msmolcic
msmolcic

Reputation: 6577

strtok() not working as expected

I'm splitting file buffer on newline delimiter using strtok() function, but the result I'm getting is not what I expected.

patient->fullName = strtok(fileContent, "\n");
patient->dateOfBirth = strtok(NULL, "\n");
patient->height = strtok(NULL, "\n");
patient->waistMeasurement = strtok(NULL, "\n");
patient->weight = strtok(NULL, "\n");
patient->comment = strtok(NULL, "\n");

When I save delimited values into struct members every member displays fine later on except the first one, fullName. If I got it right it displays address value instead. Here is the output:

enter image description here

Since I'm still not familiar with C, could you please tell me how can I get full name that's actually written in the file in the place of this pointer address?

EDIT:

Creation of fileContent:

FILE *file = fopen(fileName, "r");

fseek(file, 0, SEEK_END);
long size = ftell(file);
rewind(file);

char *fileContent = malloc(size + 1);
fread(fileContent, size, 1, file);

Patient:

struct Patient
{
    char *fullName;
    char *dateOfBirth;
    char *height;
    char *waistMeasurement;
    char *weight;
    char *comment;
};

struct Patient *patient = malloc(sizeof(*patient));

patient->fullName = malloc(sizeof(NAME_LENGTH));
patient->dateOfBirth = malloc(sizeof(BIRTHDAY_LENGTH));
patient->height = malloc(sizeof(HEIGHT_LENGTH));
patient->waistMeasurement = malloc(sizeof(WAIST_LENGTH));
patient->weight = malloc(sizeof(WEIGHT_LENGTH));
patient->comment = malloc(sizeof(COMMENT_LENGTH));

File content saved in file (it's encrypted though):

Qevms Wqspgmg
49.46.5336.
534,9
84,7
28,6
Li'w jygomrk eaiwsqi hyhi!

Upvotes: 0

Views: 654

Answers (1)

Jonathan Leffler
Jonathan Leffler

Reputation: 755114

Note that the space allocated by the malloc() calls is all lost by your use of strtok() — you are leaking. You need to use strcpy() to copy strings into the allocated space. You need to check that you allocated enough space before you copy. Or you could use the POSIX function strdup() — patient->fullName = strdup(strtok(fileContent, "\n"));. (That's a tad risky; I'd usually check the return from strtok() before passing it to strdup() — but it makes the point.)

Also, because you're copying pointers to fileContent, if you read the next line into fileContent, it will change the values of the strings pointed at by the previous patient record. Or, when fileContent goes out of scope and is used for another purpose, the data will change again.

Upvotes: 3

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