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

// This is what we would do if we didn't have a UNION.  It WASTES MEMORY!

typedef struct { // WHAT?!?!?!?!?!  This is a ** STRUCT ** type
    int    as_int;    // 4 bytes
    float  as_float;  // 4 bytes
    double as_double; // 8 bytes (?)
    char*  as_string; // 8 bytes
} Number;            // 24 bytes because for struct, size is the sum
                     //         of the size of each field.*
                     //    (* might include padding from compiler)

#define log_int(x) printf("%s == %d\n", #x, (x))
#define log_float(x) printf("%s == %.060f\n", #x, (x))
#define log_double(x) printf("%s == %.060lf\n", #x, (x))
#define log_str(x) printf("%s == \"%s\"\n", #x, (x))
#define log_sizeof(x) printf("sizeof(%s) == %zd\n", #x, sizeof((x)))

// COMPILER WILL NOT KEEP TRACK OF WHAT TYPE YOU STORED.

// If you write to a union variable after it is inialized, the new value
// overwrites the old one.

int main(int argc, char* argv[]) {
    Number n1 = { .as_int = 8 };
    log_int(n1.as_int);
    log_sizeof(n1.as_int);
    log_sizeof(n1);

    Number n2 = { .as_float = 0.125 };
    log_float(n2.as_float);
    log_sizeof(n2.as_float);
    log_sizeof(n2);

    Number n3 = { .as_double = 0.125 };
    log_double(n3.as_double);
    log_sizeof(n3.as_double);
    log_sizeof(n3);

    Number n4 = { .as_string = "8 billion" };
    log_str(n4.as_string);
    log_sizeof(n4.as_string);
    log_sizeof(n4);

    n4.as_int = 1024;
    log_int(n4.as_int);
    log_str(n4.as_string);

    return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */