file input/output

[Sean Gilbride]

trying to write a file with two user prompts i.e.
int code & string title

form this i wish to be able to read back the same information from the file. i can write the file however i cannot read back the file information one line at a time.


e.g.

0001 shriek
0002 starwars
etc;

can anyone help please........
sean.

[Shiro]

How did you open the file? I think you opened it as write-only, you should open it for read-write.

[Sebastiani]

Place them in an array of structures to do it, opening the file in the binary read/write mode. Use fwrite and fread.
Otherwise use a text file and open it in the standard read/write mode, and use fprintf and fscanf.

this loop should work, for instance, on a text file, with an array of ints and strings:

int code[size];
char title[size][length];
int x = 0;

while(!foef(fp) && x++ < size)

fscanf("%i %s", &code[x], &title[x]);

[Prelude]

An array of structs or even a linked list would work.
struct data { char line[LEN]; } array[SIZE];
or
struct data { int code; char title[LEN]; } array[SIZE];

Read from the file until you don't have any more lines:

while ( fgets( array[i].line, sizeof( struct data ), IN ) != NULL ) {
  /* Parse the line and process */
  i++;
}
or
while ( fread( array[i], sizeof( struct data ), 1, IN ) != 0 ) {
  /* Process each struct as you read it */
  i++;
}

Try to stay away from using feof() as your conditional for stopping the loop, you'll end up reading one line too many and the last struct will probably be garbage.

Too tired, need sleep...

-Prelude