problem with fread/fwrite

[Doug Gwyn]

In article <402 at bally.Bally.COM> siva at bally.Bally.COM (Siva Chelliah) writes:
-  fp = fopen("temp.dat","r+b");
-  fread(tbuf,sizeof(tbuf),1,fp);
-  fwrite(buf,sizeof(buf),1,fp);
-line 0line 1line 2line 3line 4line 0line 4
-Can you believe this?

Sure.

-When I used fseek before fwrite, it worked.  I do not remember reading 
-anywhere that I should do a fseek before fread/fwrite.

The exact requirement is spelled out quite explicitly in the C standard,
section 4.9.5.3.  I won't bore you with the technical reasons, but this
was not an oversight nor necessarily sloppiness on the part of your C vendor.