The size of a union

/* 2003.c The size of a union */
/*The size of a union is the same as the size of the largest member in the union.
The size of a structure is equal to the sum of sizes of its members instead of the size of the largest member. */

#include <stdio.h>
#include <string.h>

main(void)
{
    union u {
    double x;
    int y;
    } a_union;

    struct s {
    double x;
    int y;
    } a_struct;

    printf("The size of double: %d-byte\n",
    sizeof(double));
    printf("The size of int: %d-byte\n",
    sizeof(int));

    printf("The size of a_union: %d-byte\n",
    sizeof(a_union));
    printf("The size of a_struct: %d-byte\n",
    sizeof(a_struct));

    return 0;
}