Reading .dat file in C missing / repeating records - c

Question

I am trying to read a structure from a .dat file...
the first integer to be read is the no of readings
then there is the data in following structure format
struct Oven
{
int rec_no;
int temp;
int status;
char string[10];
};
below is the method through which I read the file
int read_and_process_file()
{
int counter;
FILE *ptr_myfile;
struct Oven my_record;
ptr_myfile=fopen("data.dat","rt");
//for no of readings
fread(&no_of_readings,sizeof(no_of_readings),1,ptr_myfile);
for ( counter=1; counter <= 50; counter++)
{
fread(&my_record,sizeof(struct Oven),1,ptr_myfile);
name=my_record.string;
printf("%d : ",my_record.rec_no);
fprintf(ptr_myfile2,"%d : ",my_record.rec_no);
printf("%d : ",my_record.temp);
printf("%d : ",my_record.status);
printf("%s\n",name);
}
fclose(ptr_myfile);
return 0;
}
but i can't read more than 25 records after 25 it keeps on repeating the 25th record...
tried fseek but it skips some records... any help?
This is the output image
UPDATE (Wildplasser) And here is the first 0x200 bytes of the data (wich does look a bit irregular ...)
00000000 b8 0b 00 00 00 00 00 00 54 00 00 00 01 00 00 00 |........T.......|
00000010 42 6f 62 00 cd cd cd cd cd cd cd cd 01 00 00 00 |Bob.............|
00000020 4d 00 00 00 00 00 00 00 43 4c 4f 53 45 44 00 cd |M.......CLOSED..|
00000030 cd cd cd cd 02 00 00 00 2e 00 00 00 00 00 00 00 |................|
00000040 43 4c 4f 53 45 44 00 cd cd cd cd cd 03 00 00 00 |CLOSED..........|
00000050 5f 00 00 00 01 00 00 00 48 61 72 72 79 00 cd cd |_.......Harry...|
00000060 cd cd cd cd 04 00 00 00 44 00 00 00 01 00 00 00 |........D.......|
00000070 48 61 72 72 79 00 cd cd cd cd cd cd 05 00 00 00 |Harry...........|
00000080 63 00 00 00 01 00 00 00 4a 69 6c 6c 00 cd cd cd |c.......Jill....|
00000090 cd cd cd cd 06 00 00 00 53 00 00 00 01 00 00 00 |........S.......|
000000a0 4a 61 6d 65 73 00 cd cd cd cd cd cd 07 00 00 00 |James...........|
000000b0 56 00 00 00 00 00 00 00 43 4c 4f 53 45 44 00 cd |V.......CLOSED..|
000000c0 cd cd cd cd 08 00 00 00 49 00 00 00 00 00 00 00 |........I.......|
000000d0 43 4c 4f 53 45 44 00 cd cd cd cd cd 09 00 00 00 |CLOSED..........|
000000e0 53 00 00 00 01 00 00 00 42 6f 62 00 cd cd cd cd |S.......Bob.....|
000000f0 cd cd cd cd 0d 0a 00 00 00 59 00 00 00 00 00 00 |.........Y......|
00000100 00 43 4c 4f 53 45 44 00 cd cd cd cd cd 0b 00 00 |.CLOSED.........|
00000110 00 46 00 00 00 01 00 00 00 4a 69 6c 6c 00 cd cd |.F.......Jill...|
00000120 cd cd cd cd cd 0c 00 00 00 38 00 00 00 00 00 00 |.........8......|
00000130 00 43 4c 4f 53 45 44 00 cd cd cd cd cd 0d 00 00 |.CLOSED.........|
00000140 00 48 00 00 00 00 00 00 00 43 4c 4f 53 45 44 00 |.H.......CLOSED.|
00000150 cd cd cd cd cd 0e 00 00 00 5e 00 00 00 01 00 00 |.........^......|
00000160 00 4a 61 6d 65 73 00 cd cd cd cd cd cd 0f 00 00 |.James..........|
00000170 00 40 00 00 00 01 00 00 00 4a 69 6c 6c 00 cd cd |.#.......Jill...|
00000180 cd cd cd cd cd 10 00 00 00 56 00 00 00 00 00 00 |.........V......|
00000190 00 43 4c 4f 53 45 44 00 cd cd cd cd cd 11 00 00 |.CLOSED.........|
000001a0 00 43 00 00 00 01 00 00 00 4a 61 6d 65 73 00 cd |.C.......James..|
000001b0 cd cd cd cd cd 12 00 00 00 60 00 00 00 01 00 00 |.........`......|
000001c0 00 42 6f 62 00 cd cd cd cd cd cd cd cd 13 00 00 |.Bob............|
000001d0 00 5e 00 00 00 00 00 00 00 43 4c 4f 53 45 44 00 |.^.......CLOSED.|
000001e0 cd cd cd cd cd 14 00 00 00 55 00 00 00 00 00 00 |.........U......|
000001f0 00 43 4c 4f 53 45 44 00 cd cd cd cd cd 15 00 00 |.CLOSED.........|

Answer 1

It's hard to tell exactly what's going on as your code snippet isn't complete, but here are some things I noticed:
You don't seem to be using the read-in no_of_readings, and instead try to read 50 records. Since you don't check the return value of fread, your program just carries on using whatever the last successful fread read.
You shouldn't be opening the file in text mode if you're not reading text. Line ending conversion could corrupt your data. Use "rb" instead (also the standard C way to open in text mode is just to omit the b, t is nonstandard).
edit: On Windows reading a file in text mode interprets a ctrl-z byte (26) as end of file. This is why your reads stop after the 25th record.
Reading/writing data directly to/from structs like this will result in data files that aren't portable. Better to serialise your struct into bytes manually.

Answer 2

I would suggest checking the return value of the fread to check for errors
int size = fread(&my_record,sizeof(struct Oven),1,ptr_myfile);
if (size != sizeof(struct Oven))
{
perror ("Error reading Line %d", counter);
break;
}
This should give an idea of what went wrong