c - Possible memory issue or something else? -

i have been working on series of tasks involving structs, reading , writing bin files in c.

the struct definition is:

struct data{     unsigned int a;     unsigned short b;     short c;     char d[8];     short e;     int f;     int g;     short h;      char i;     char j;     unsigned long k;     char l;     double m;     float n;     int o;     char p;     double q; } 

my reading , printing program seems working fine, code is:

int main (int argc, char **argv){     // check correct number of args     file *record = fopen(argv[1], "r")     // more prelim checks      struct data entry;      /* if first field exists, task assumption other fields      *   must exist proper sizes.      */     while(fread(&entry.a, sizeof entry.a, 1, record) > 0){         fread(&entry.b, sizeof entry.b, 1, record);         // ... read fields 1 one         fread(&entry.q, sizeof entry.q, 1, record);         printf("%u, %d, %d, %s, %d, %d, %d, %d, %c, %lu, %hhx, %f, %f, %d, %d, %f",                  entry.a, entry.b, entry.c . . . entry.q);     } } 

this prints out input bin file without error (tested automatically against 15 files, tens of entries). simplest one, 1 entry,

however, when try store data can sorted, using following array, data starts off correctly, goes haywire far can see:

    struct data *entries = null;     int curentries = 100;     int counter = 1;     entries = (struct data *) malloc(curentries * sizeof(struct data));     while(fread(&entries[counter - 1].a, sizeof entries[counter - 1].a, 1, record) >0){         /* same reading, storing , printing above, increment counter */     } 

since reading , printing parts same, other use of "counter" variable, problem here array memory, , need fix?

edit: solved. implementation correct, many of these comments formatting , use of variables extremely helpful. issue difference in format had code for.