Pointer of array of structure

Question

Ok, I've got this code :

#include <stdio.h>
#include <stdlib.h>

#define ARR_SIZE 5

struct mys
{
    double first;
    unsigned long second;
    char str[10];
};

int main(int argc, char** argv)
{
    size_t i = 0;
    struct mys thes[ARR_SIZE] = 
        {
            {1.1, 1, "First"},
            {2.2, 2, "Second"},
            {3.3, 3, "Third"},
            {4.4, 4, "Fourth"},
            {5.5, 5, "Fifth"}
        };//load array of structures with values

    for (; i < ARR_SIZE; ++i)
        fprintf(stdout, "second->%lu\n", thes[i].second);//loop through array thes and print element second

    return (EXIT_SUCCESS);
}

Now, I want to get the address of the element called second of the zeroth element thes and then use that to loop through the array thes and print each second element.

#include <stdio.h>
#include <stdlib.h>

#define ARR_SIZE 5

struct mys
{
    double first;
    unsigned long second;
    char str[10];
};

int main(int argc, char** argv)
{
    size_t i = 0;
    unsigned long * ptr = NULL;//pointer to unsigned long
    struct mys thes[ARR_SIZE] = 
        {
            {1.1, 1, "First"},
            {2.2, 2, "Second"},
            {3.3, 3, "Third"},
            {4.4, 4, "Fourth"},
            {5.5, 5, "Fifth"}
        };

    //first loop
    for (; i < ARR_SIZE; ++i)
        fprintf(stdout, "second->%lu\n", thes[i].second);

    ptr = &thes[0].second;//get the address of the second element of the zero'th array structure and store it in ptr

    // Now I want to use the above pointer ptr to loop through the array thes and display the second element like I did above, but I can't manage to do that.
    //The output of this loop should be the same as the first loop 

    return (EXIT_SUCCESS);
}

So, I've implemented the pointer but I'm having problem writing the code for the second loop. Any help is appreciated.

Answer 1

for (; i < ARR_SIZE; ++i)
    fprintf(stdout, "second->%lu\n", *( unsigned long * )(( char * )ptr + i * sizeof( struct mys ) ));