Reading string and integer from file into struct - C

Question

I hope this question isn't too similar to another that's posted. I am still learning how to read other peoples code at this point let alone write my own. I am confused as to how to read both a string and int from a line in a file and store it in a struct called People. I have been looking at fgets, fscanf and even fread but I can't figure out what to use and where to use it. I am getting this data from a file with a max of 10 entries that looks like this:

Joshua 50
Dwayne 90
Jennifer 45
Goldilocks 85

Here is my code:

typedef struct
{
    char *name[20];
    int change_amount;
    int fifties;
    int twenties;
    int tens;
    int fives;
}People;

int get_file()
{
    const int MAXPEOPLE = 10;
    People persons[MAXPEOPLE];
    int i = 0;
    FILE *fpointer;
    char line[12];
    fopen("file.txt", "r");
    if (fpointer == NULL)
    {
        perror("Error opening file");
        return (0);
    }
    while (fgets(line, 8, fpointer) != NULL)
    {
        //Max number of letters for name under assumption is 8
        char name[8];
        int amount = 0;
        scanf(line, "%s %d", name, amount);
        printf("%s", name);
        memset(line, 0, 8);
        for (int i = 0; i < MAXPEOPLE; ++i)
        {
            return(0);
        }
    }
}

Any help is appreciated. Go easy on me :)

You are ignoring the helpful return value at your own risk. It could help you debug. — Yunnosch
– Yunnosch, Commented Jun 3, 2020 at 5:28
You are not confusing sscanf() and scanf(), are you? Seems like you read into line with fgets()(wise move) and then try to scan from there, but use the wrong function to do so. — Yunnosch
– Yunnosch, Commented Jun 3, 2020 at 5:29
You only live twice, but you can only return once: your loop is pointless:( — Martin James
– Martin James, Commented Jun 3, 2020 at 5:32
You call fopen() but don't assign (or check) the returned value. You then test the still uninitialized fpointer. Not a recipe for happiness! — Jonathan Leffler
– Jonathan Leffler, Commented Jun 3, 2020 at 5:33
I assume you are fine with me adding those things to my answer. — Yunnosch
– Yunnosch, Commented Jun 3, 2020 at 5:34

Yunnosch · Accepted Answer · 2020-06-03 05:37:29Z

1

I think the main issue with getting the scanning right is that you read into line with fgets()(wise move) and then try to scan from there.

scanf(line, "%s %d", name, amount);

but use the wrong function to do so. Use sscanf().
https://en.cppreference.com/w/c/io/fscanf

For completeness let me add the contribution from comments by Martin James and Jonathan Leffler:

You only live twice, but you can only return once: your loop is pointless

I.e. once any iteration of your for loop has a return, and all of them have, your while loop is finished.

You call fopen() but don't assign (or check) the returned value. You then test the still uninitialized fpointer. Not a recipe for happiness!

I.e. this

fopen("file.txt", "r");
if (fpointer == NULL)

should be

fpointer = fopen("file.txt", "r");
if (fpointer == NULL)

edited Jun 3, 2020 at 5:37

answered Jun 3, 2020 at 5:32

Yunnosch

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2 Comments

Anuthacodingnoob Over a year ago

Thanks so much! Just reading through all the comments. It's amazing how quickly this community has responded. Thankyou also for formatting my question properly :)

Yunnosch Over a year ago

It is such a rare pleasure to give a nice impression to a new member. Have fun.

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