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

union Data {
   int i;
   float f;
   char str[20];
};

int main( ) {

   union Data data;
   //-----------------------------------------------------------
   // try one of this, for example
   //-----------------------------------------------------------
   // data.f = 0.1;
   data.i = 'A';
   // strcpy(data.str, "ABCD\0");
   //-----------------------------------------------------------
   printf( "Memory size occupied by data : %lu\n", sizeof(data));
   printf("Data as int: %d\n", data.i);
   printf("Data as float: %f\n", data.f);
   printf("Data as char: %s\n", data.str);
   return 0;
}