如何在c中通过引用传递typedef结构

Question

i am trying to load data points in a txt file to a typdef struct dataset , i need a function that will split the dataset to training and testing, so it must be return two values, in c this can be done using void methods that takes params by ref, it works like this for example

#include<stdio.h>
void div(int a, int b, int *quotient, int *remainder) {
   *quotient = a / b;
   *remainder = a % b;
}
main() {
   int a = 76, b = 10;
   int q, r;
   div(a, b, &q, &r);
   printf("Quotient is: %d\nRemainder is: %d\n", q, r);
}

However if the param is a struct as in my case, it seems that values are not updated and remain as at the moment of initialization.

My Question is how to make this work for struct so some thing like this will work

dataset *trainset, *testset;

trainset = load(filename, ratio, &testset);

The typedef struct are:

typedef struct data_member {
    double*         inputs;         /* The input data */
    double*         targets;        /* The target outputs */
} data_member;

typedef struct dataset{
    data_member*    members;        /* The members of the dataset */
    int             num_members;    /* The number of members in the set */
    int             num_inputs;     /* The number of inputs in the set */
    int             num_outputs;    /* The number of outputs in the set */
} dataset;

and the format of the file passed is

<Nrows> <Ninputs> <Noutputs>
<i1> <i2> <i3>.. <iN> <o1>... <oN>
<i1> <i2> <i3>.. <iN> <o1>... <oN>
<i1> <i2> <i3>.. <iN> <o1>... <oN>
<i1> <i2> <i3>.. <iN> <o1>... <oN>
..
..
<i1> <i2> <i3>.. <iN> <o1>... <oN>

Thanks

Answer 1

This is how you could call it:

---

typedef stuct dataset {
        struct data_member *members;
        unsigned num_members;
        unsigned num_inputs;
        unsigned num_outputs;
        } Dataset;
int load_data(Dataset *result, FILE *fp);

int main(void)
{
int rc;
FILE *fp;
Dataset the_data = {NULL, 0,0,0};

fp = fopen ("the_file", "r");
rc = load_data( &the_data, fp);

fclose (fp);
return 0;
}

int load_data(Dataset *result, FILE *fp)
{
/* ... your code here ...  */
return 13;
}