Question

I have create a struct and it has its id number, its value, and its status.
I have a file that consist of the data(1 199 0 2 199 1…) 1 its the number, 199 is the value, 0 is the status and keep going like this…
I have used 1 function called filldata() to read 3 numbers at a time, which are for example, 1 199 0 and then put it into the passed element of a struct array.
And then, i used another function to call the this function to fill up the struct array.
The fillAll function will return the set of data tha.t had been copied from the file to the struct array
But i received a segmentation fault. Any idea why?
The codes explain better:

int filldata(struct Data_point *a, const char *filelocation)  
    {

        FILE *f;
        if((f=fopen(filelocation,"r"))==NULL)
            printf("You cannot open");

        if( fscanf(f, "%ld%lf%d", &(a->sampleNumber), &(a->value), &(a->status)) == 3)
            return 1;   
        else
            return 0;
    }

    int fillAll(struct Data_point *a, const char *filelocation)// I will pass the struct array and the location of my file string
    {
        int index=0;
        while(filldata(&a[index], filelocation))
            index++;

        return index;
    }

Answer 1

you repeatedly open filename filelocation but never close the file handle f. You would keep reading the first line over and over again and eventually run out of filehandles.

You can change filldata to take the file pointer check the snippet below i have added
some additional checks , you also need to check the size of Data_point *a is within the
allocated range as you fill it up

int filldata(struct Data_point *a, File *f) 


    if( fscanf(f, "%ld%lf%d", &(a->sampleNumber), &(a->value), &(a->status)) == 3)
        return 1;   
    else
        return 0;
}

int fillAll(struct Data_point *a, const int data_point_size,const char *filelocation)// I will pass the struct array and the location of my file string
{

    FILE *f;
    if((f=fopen(filelocation,"r"))==NULL) {
        printf("You cannot open");
       return 0;
    }


    int index=0;
    while(index < data_point_size &&  filldata(&a[index]))  {
        index++;
    } 
    fclose(f);
    return (index != data_point_size);
 }