Shows that (in practice, not standard) structs are just a fancy linear container of their types (assuming alignment works out) in memory

coord.c

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

struct coord {
    int x;
    int y;
    int z;
};

int main(void)
{
    struct coord *v = malloc(sizeof(struct coord) * 2);
    int *ptr = (int*)v;

    for (int i = 0; i < 6; i++)
        ptr[i] = 100 + i;

    for (int i = 0; i < 2; i++)
        printf("v[%d] = {%d, %d, %d}\n", i, v[i].x, v[i].y, v[i].z);

    return 0;
}

$ gcc -Wall -Wextra -Wpedantic -o test test.c; ./test
v[0] = {100, 101, 102}
v[1] = {103, 104, 105}