Won't read from file to struct - c

Question

I've been sitting with this problem for 2 days and I can't figure out what I'm doing wrong. I've tried debugging (kind of? Still kind of new), followed this link: https://ericlippert.com/2014/03/05/how-to-debug-small-programs/ And I've tried Google and all kinds of things. Basically I'm reading from a file with this format:
R1 Fre 17/07/2015 18.00 FCN - SDR 0 - 2 3.211
and I have to make the program read this into a struct, but when I try printing the information it comes out all wrong. My code looks like this:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAX_INPUT 198
typedef struct game{
char weekday[4],
home_team[4],
away_team[4];
int round,
hour,
minute,
day,
month,
year,
home_goals,
away_goals,
spectators;}game;
game make_game(FILE *superliga);
int main(void){
int input_number,
number_of_games = 198,
i = 0;
game tied[MAX_INPUT];
FILE *superliga;
superliga = fopen("superliga-2015-2016.txt", "r");
for(i = 0; i < number_of_games; ++i){
tied[i] = make_game(superliga);
printf("R%d %s %d/%d/%d %d.%d %s - %s %d - %d %d\n",
tied[i].round, tied[i].weekday, tied[i].day, tied[i].month,
tied[i].year, tied[i].hour, tied[i].minute, tied[i].home_team,
tied[i].away_team, tied[i].home_goals, tied[i].away_goals,
tied[i].spectators);}
fclose(superliga);
return 0;
}
game make_game(FILE *superliga){
double spect;
struct game game_info;
fscanf(superliga, "R%d %s %d/%d/%d %d.%d %s - %s %d - %d %lf\n",
&game_info.round, game_info.weekday, &game_info.day, &game_info.month,
&game_info.year, &game_info.hour, &game_info.minute, game_info.home_team,
game_info.away_team, &game_info.home_goals, &game_info.away_goals,
&spect);
game_info.spectators = spect * 1000;
return game_info;
}

Answer 1

The problem is in your file. It starts with whitespaces, not with R's as you stated in the control string.
Check the return value of fscanf() and you'll see that it's zero everytime.
If you add a leading whitespace to your fscanf() call, your problem will be solved, like this:
fscanf(superliga, " R%d %s %d/%d/%d %d.%d %s - %s %d - %d %lf\n",
&game_info.round, game_info.weekday, &game_info.day, &game_info.month,
&game_info.year, &game_info.hour, &game_info.minute, game_info.home_team,
game_info.away_team, &game_info.home_goals, &game_info.away_goals,
&spect);

Answer 2

If each line in the file is a separate record, you should read each line as a string, then try to parse each string.
(Note that this also has the added feature of speculative parsing: you can try parsing the line in several different formats, and accept the one that parses correctly. I like to use this when I accept e.g. vector inputs, so that the user can use x y z, x, y, z, x/y/z, (x,y,z), [x,y,z], <x y z>, <x,y,z>, and so on, depending on what they like. It's only one additional scanf per format, after all.)
To read lines, you can use fgets() into a local buffer. The local buffer must be long enough. If the program is to run on POSIX.1 machines only (i.e., not on Windows), then you can use getline() instead, which can dynamically reallocate the given buffer as needed, so you're not limited to any specific line length.
To parse the string, use sscanf().
Note that all tabs, spaces, and newlines in the pattern in all of the scanf family of functions are treated exactly the same: they indicate any number of any type of whitespace. In other words, \n does not mean "and then a newline"; it means the same as a space, i.e. "and possibly some whitespace here". However, all conversions except %c and %[ automatically skip any leading whitespace; so, with the exception of a space before one of those two, the spaces in the pattern are only meaningful to us humans, they do not have any functional effect in the scanning.
All scanf family of functions return the number of successful conversions. (The only exception is the "conversion" %n, which yields the number of characters consumed; some implementations include it in the conversion count, and some others do not.) If end of input occurs prior to the first conversion, or a read error occurs, or the input does not match with the fixed part of the pattern, the functions will return EOF.
Even if you suppress saving the result of a conversion -- for example, if you have a word in the input you don't need, you can convert but discard it with %*s --, it is counted. So, for example sscanf(line, " %*d %*s %*d") returns 3 if the line starts with an integer, followed by a word (anything that is not a newline nor contains whitespace), followed by an integer.
Rather than have the function return the parsed structure, pass a pointer to the structure (and the file handle to read from), and return a status code. I prefer 0 for success, and nonzero for failure, but feel free to change that.
In other words, I'd suggest you change your read function into
#ifndef GAME_LINE_MAX
#define GAME_LINE_MAX 1022
#endif
int read_game(game *one, FILE *in)
{
char buffer[GAME_LINE_MAX + 2]; /* + '\n' + '\0' */
char *line;
/* Sanity check: no NULL pointers accepted! */
if (!one || !in)
return -1;
/* Paranoid check: Fail if read error has already occurred. */
if (ferror(in))
return -1;
/* Read the line */
line = fgets(buffer, sizeof buffer, in);
if (!line)
return -1;
/* Parse the game; pattern from OP's example: */
if (sscanf(line, "R%d %3s %d/%d/%d %d.%d %3s - %3s %d - %d %d\n",
&(one->round), one->weekday,
&(one->day), &(one->month), &(one->year),
&(one->hour), &(one->minute)
one->home_team,
one->away_team,
&(one->home_goals),
&(one->away_goals),
&(one->spectators)) < 12)
return -1; /* Line not formatted like above */
/* Spectators in the file are in units of 1000; convert: */
one->spectators *= 1000;
/* Success. */
return 0;
}
To use the above function in a loop, reading games one after another from standard input (stdin):
game g;
while (!read_game(&g, stdin)) {
/* Do something with current game stats, g */
}
if (ferror(stdin)) {
/* Read error occurred! */
} else
if (!feof(stdin)) {
/* Not all data was read/parsed! */
}
The two if clauses above are to check if there was a real read error (as in, a problem with the hardware or something like that), and whether there was unread/unparsed data (not at end of file), respectively.
There are two differences in the scanning pattern compared to the OP: First, all strings parsed are limited to 3 characters, because the structure has only room for 3+1 each. The one character is reserved for the end of string '\0', which is not counted in the maximum length for %s. Second, I parse the spectator count directly, and just multiply the field by 1000 if successful.
Also note how I used one->weekday, one->home_team, and one->away_team to refer to the character arrays. This works, because an array variable can be used as if it was a pointer to the first element in that array. (Given char a[5];, a and &a and &(a[0]) can all be used to refer to the first element in the array a). I like to use this "raw form" when scanning, because it makes it easier to match them to %s conversions, and ensure the pattern matches the parameters.