fscanf for int and float returns large value for int, and NAN for float

Question

I am trying to store a series of values from a configuration file which have data types of int and float. I'm not sure why, but when I print the values inside the array, the int value returns a large number, and the floats return NAN.

Configuration file:

1666    -0.314913523    0.999804843
1667    -0.337279687    0.999865966
1703    -0.323162231    0.999774194
1704    -0.311984064    0.99964375
1705    -0.311984064    0.99964375
1706    -0.313381260    0.999671436
1707    -0.313170802    0.999558174

My code:

#include <iostream>
using namespace std;

#define NUM_ITEMS 50
int main()
{
    FILE *fp;
    fp = fopen("config.conf","r");
    

    int a[NUM_ITEMS][NUM_ITEMS];
    float b[NUM_ITEMS][NUM_ITEMS];
    float c[NUM_ITEMS][NUM_ITEMS];

    int i = 0;

    while(fscanf(fp,"%i\t%f\t%f", a[i], b[i], c[i]) != EOF)
    {
        printf("%i  %f  %f\n", a[i], b[i], c[i]);
        i++;
    }
    
    fclose(fp);
}

output:

1149516976      -nan    0.000000
1149517176      -nan    0.000000
1149517376      -nan    0.000000
1149517576      -nan    0.000000
1149517776      -nan    0.000000
1149517976      -nan    0.000000
1149518176      -nan    0.000000

Answer 1

    int a[NUM_ITEMS][NUM_ITEMS];
    float b[NUM_ITEMS][NUM_ITEMS];
    float c[NUM_ITEMS][NUM_ITEMS];

This makes a, b, and c arrays of arrays, so a[i] is an array. You want:

    int a[NUM_ITEMS];
    float b[NUM_ITEMS];
    float c[NUM_ITEMS];

So that a is an array of ints and now a[i] is an int. You need to pass the address to scanf though.

Here's the code with all major issues fixed:

#include <iostream>

#define NUM_ITEMS 50
int main()
{
    FILE *fp;
    fp = fopen("config.conf","r");
    if (fp == NULL)
        return -1;
    

    int a[NUM_ITEMS];
    float b[NUM_ITEMS];
    float c[NUM_ITEMS];

    int i = 0;

    while(fscanf(fp,"%i\t%f\t%f", &a[i], &b[i], &c[i]) == 3)
    {
        printf("%i  %f  %f\n", a[i], b[i], c[i]);
        i++;
    }
    
    fclose(fp);
}