Problem with reading/writing files

[kinghajj]

void add_person(Control *c)
{
	char line[1024];
	char buff[1024];
	if((file = fopen(filename,"r+")) == NULL)
	{
		error(app,"Could not open file main.add!");
	}
	fgets(buff,1024,file);
	fputs(buff,file);

	strcat(line,"<");
	strcat(line,get_control_text(mainw.f_lname));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_fname));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_add));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_st));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_zip));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_home));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_work));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_cell));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_bd));
	strcat(line,"|");
	strcat(line,get_control_text(mainw.f_rel));
	strcat(line,">");
	ask_ok(app,"TEST",line);
	fputs(line,file);
	fclose(file);
	clear_boxes();
	free(buff);
	free(line);
}

when I add one person, I get this "<|||||||||>", but when I add another, I get "<|||||||||><|||||||||><|||||||||>".

Why?

[XSquared]

char line[1024];
char buff[1024];

You should add = { '\0' }; to the end of those two statements. Local variables are not guaranteed to be allocated to zero. Most likely, the old data is still there.

free(buff);
free(line);

You only use free when you malloc( ) something.

[kinghajj]

so write:

char line[1024] = { '\0' };

I'll try that (for both chars).

[kinghajj]

that didn't fix it >

... what if they were global?

[kinghajj]

... is there a function that completely NULLs a string?

[Fahrenheit]

Originally posted by kinghajj
... is there a function that completely NULLs a string?

memset(string,0,string_length) ;

[kinghajj]

still doesn't work...

[XSquared]

Try outputting the contents of buff and of line to the screen, and see what shows.

[kinghajj]

... I solved it... but it doesn't make sence...

I deleted this line:

fputs(buff,file);

... that shouldn't work... I thought that fputs overwrites what is currently in the file. I guess not

[quzah]

Originally posted by kinghajj
I thought that fputs overwrites what is currently in the file. I guess not

How data is sent to your file depends entirely on how you open the file.

Quzah.

[kinghajj]

how so?

[WaltP]

Your first strcat() should be strcpy(). This will erase the old contents of the buffer and start fresh. No need to erase the buffer before using then.

Or, instead of making all those strcat() calls, how about:

sprintf(line,
        "<%s|%s|%s|%s|%s|%s|%s|%s|%s|%s>",
        get_control_text(mainw.f_lname),
        get_control_text(mainw.f_fname),
        get_control_text(mainw.f_add),
        get_control_text(mainw.f_st),
        get_control_text(mainw.f_zip),
        get_control_text(mainw.f_home),
        get_control_text(mainw.f_work),
        get_control_text(mainw.f_cell),
        get_control_text(mainw.f_bd),
        get_control_text(mainw.f_rel));

Also, why are you doing an fgets() then immediately an fputs() to the file?
The logic escapes me.

[Salem]

The main reason I can see is that you're reading and writing the same file.

So open two files - one for reading, and another for writing.

> strcat(line,"<");
line is uninitialised, unless you initialise it like XSquared showed you.
Another way is to do
strcpy( line, "<" );
and the rest can be strcat() calls