writing into a file

I am facing a weird problem when i try to write the contents of a char array into a file.

I first do:

Code:

---

      fp=fopen(filename,"w");
      fprintf( fp1 ,"%s" , buf);
      fclose(fp);

---

here, buf points to the starting location of my char array...

the contents of this array will be re-written during the execution , and so, to transfer the new content into a file I do :

Code:

---

      fp=fopen(filename,"a");
      fprintf( fp1 ,"%s",buf);
      fclose(fp);

---

again , here buf points to the start ...

the problem is : after the execution , when i open the file with "cat" , the contents of the file is displayed correctly..

when i open it thru a text editor, I see non-ascii characters at the end of each line

Well since your other threads involve reading from the network, my guess is your strings lack a \0 in the correct place, so you end up with random junk after each bit of valid text.