fread() questions.

Hey guys,
im reading a binary file and then using fprintf to write the data to a text file.
the sequence of each line is first, an (unsigned char) that determines the length of the string that follows, the string itself, and an integer right after it.
My file is supposed to look like this:
a 74
abc 973
defghij 0
input.dat 1
output.dat 2745
ThisIsaLongStringAndItIsDeliberatelySo 36745
ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWX YZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUV WXYZABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrst uvwxyabcdefghijklmnopqrstuvwxyabcdefghijklmnopqrst uvwxyabcdefghijklmnopqrstuvwxyabcdefghijklmnopqrst uvwxy 123456

but instead I get:
a 74
abcÿ 973
defghij 0
input.dat 1
output.dat 2745
ThisIsaLongStringAndItIsDeliberatelySoã¨ÿ¿ù€ÿ*ˆ.. 36745
ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWX YZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUV WXYZABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrst uvwxyabcdefghijklmnopqrstuvwxyabcdefghijklmnopqrst uvwxyabcdefghijklmnopqrstuvwxyabcdefghijklmnopqrst uvwxy 123456

which is almost identical except from line 2 and 6 (i made bold for emphasis). The integers are correct which makes it more difficult to understand where the error is.

here is my code:

Code:

---


void writeTextFile(FILE *finp, FILE *fop){

        char string[256];
        int fileLen, theinteger, pos;
        unsigned char num1;

        fseek(finp, 0L, SEEK_END);
        fileLen = ftell(finp);            //highest offset
        rewind(finp);

        while(pos < fileLen){      //do while offset is less than fileLen
                fread(&num1, sizeof(unsigned char), 1, finp); //num1 determines how long the string that follows is
                fread(string, sizeof(char), num1, finp); //read the string
                fprintf(fop, "%s\t", string);                  //print the string
                fread(&theinteger, sizeof(int), 1, finp); //read the integer that comes right after the string
                fprintf(fop, "%d\n", theinteger);        //print the integer
                pos = ftell(finp);
        }//end while
}//end function

---

when reading an integer, does fread() move the file offset by 1 or by the size of the int (4bytes on my machine).
I asume that fread moves the file offset by n when reading a string of size n.
Why does my code have extra junk in it but at the same time it doesnt effect the reading of other elements in the file.
Any thoughts?
Thanks

Do you NULL terminate the array string[] after reading characters from the binary file into it?

note that ftell returns long - so better adjust the type of the variable that stores the result

and you actually do not need it (it could fail on very long files) - just check the return value of each fread...

also your function name is confusing - you calling it write something, while actually reading something