/* This program illustrates the union data type. The three fields
   num.integer_num, num.unsigned_num, and num.float_num are initially
   set to 0. Only num.integer_num is modified to -1. However, the
   values of num.unsigned_num and num.float_num are all changed because
   the three fileds share the same memory location.
*/
#include <stdio.h>

int main(void) {

  union number_union {
    int      integer_num;
    unsigned unsigned_num;
    float    float_num;
  } num;

  num.integer_num = 0;
  num.unsigned_num = 0;
  num.float_num = 0;

  num.integer_num = -1;
  printf("Integer: %d\n", num.integer_num);
  printf("unsigned: %u\n", num.unsigned_num);
  printf("float: %f\n", num.float_num);

  printf("address of num.integer_num: 0X%X\n", &num.integer_num);
  printf("address of num.unsigned_num: 0X%X\n", &num.unsigned_num);
  printf("address of num.float_num: 0X%X\n", &num.float_num);
  
  system("pause");
  return 0; 
}