Help on fwrite

[dollylamb]

Hi guys,

I wrote a program to read DBF file header, content & do some search/delete on records. All others function work fine but delete function doesn't works or exactly it make DBF corrupted after writing deletion mark. The deletion code look like this:

assume that i want to mark delete record number 10

FILE * f = fopen(myFile. "rb");
DBF_HEADER header;
DBF_FHEADER *fields;
int fcount;
int deleteRec = 10;
char *delMark = "*";
int bytesWritten;

//read header
fread(&header, sizeof(header), 1, f);
fcount = (header.headerlen - 33) / 32;  //get total fields

//init & read fields header
fields = new struct DBF_FHEADER[fcount];
fread(fields, sizeof(DBF_FHEADER), fcount, f);

//move to record 10 & take a look at it.
fseek(f, (10-1) * header.RecordLen, SEEK_CUR);
char p;
p = fread(&p, sizeof(char), 1, f);
if(p == "*"){
     cout << "Cannot delete a deleted record." << endl;
     return 0;
}
fclose(f);

//now start to mark delete given record
f = fopen(myFile, "wb");

//move cursor over main header & field header
fseek(f, 32 + (32 * fcount) + 1, SEEK_CUR); 

//move to given record
fseek(f, (10 - 1) * header.RecordLen, SEEK_CUR);

//now write * to the first byte of record string.
bytesWritten = fwrite(delMark, 1, 1, f);
//bytesWritten now has value of 1 indicate that write function completed successfully.

fclose(f); 

the code above successfully write a byte to dbf file but it also destroys my DBF file (file size after writing task reduced from > 2 MB to ~520KB) anyone knows what happens to my file? please give me an advice. Thanks.