Referencing the same memory in different ways

/* 2004.c: Referencing the same memory in different ways */
#include <stdio.h>

union u{
char ch[2];
int num;
};

int UnionInitialize(union u val);

main(void)
{
    union u val;
    int x;

    x = UnionInitialize(val);

    printf("The two character constants held by the union:\n");
    printf("%c\n", x & 0x00FF);
    printf("%c\n", x >> 8);

    return 0;
    }
    /* function definition */
    int UnionInitialize(union u val)
    {
    val.ch[0] = 'H';
    val.ch[1] = 'i';

    return val.num;
}