Printf gives segmentation fault unless I do a "printf" first

I'm trying to import data from a file but I made a mistake (after this code below) so I was going to make some debugging, adding so the 15th line of this code:

fscanf(input, "%d %d", & numofusers, & numofmovies);
//-----users list allocation
for (int i = 0; i < numofusers; i  ) {
    curruser -> usercode = i   1;

    //without this 7th line I get a segmentation fault at line 15 (without line 15 program termines successfully)
    printf("%d %d %d\n\n", numofusers, numofmovies, curruser -> usercode);
    //through this line of code I understood that it does what I want it to do

    curruser -> next = calloc(1, sizeof(struct user * ));
    curruser = curruser -> next;
}
curruser = headuser;
//--------
printf("!%d!\n", numofmovies);

The first line of the file contains two integers, which are read with no issues, then I try to allocate some memory for the users. If the first printf is there, no segmentation fault and everything works; otherwise it doesn't. I've already tried some potential solutions from this website but they didn't fix the issue. There must be somewhere I'm not aware of...

CodePudding user response：

You're allocating the wrong amount of memory:

calloc(1, sizeof(struct user * ));

You are allocating enough memory for a pointer, not a whole object.

It should be

calloc(1, sizeof(struct user));

(And, there's no reason to use calloc here over malloc.)