#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
#include "clog.h"

// Q: Can I avoid typing "struct"?
// A: Use typedef.  Essentially, this creates a type with a shorter name.  There's a 
//    derivation which will explain why this works, which I'll go over another day.
//
// struct Point { int x; int y; };
// struct Point p = { .x = 5, .y = 6};
//
// .... equivalent to ...
//
// typedef struct { int x; int y; } Point;
// Point p = { .x = 5, .y = 6};
//
// and likewise for a union or enum.

typedef struct {
    union {
        int as_int;
        double as_double;
    };  // OMIT NAME to make an anonymous union inside the struct.  (C11)

    // } value;

    enum NumberType {
        NUMBER_INT,    // 0
        NUMBER_DOUBLE  // 1
    } type;  // field name is here <<<<<<
} Number;

void print_number_value(Number n) {
    if(n.type == NUMBER_INT) {
        printf("%d\n", n.as_int);
        //printf("%d\n", n.value.as_int);
    }
    else if(n.type == NUMBER_DOUBLE) {
        printf("%f\n", n.as_double);
        //printf("%f\n", n.value.as_double);
    }
}

int main(int argc, char* argv[]) {

    printf("Declare and initialize n to 5 (as an int).\n");
    // union NumberValue n = { .as_int = 5 };
    // enum NumberType type_of_n = NUMBER_INT;
    Number n = { .as_int = 5, .type = NUMBER_INT };

//  print_number_value(n, type_of_n);
    print_number_value(n);

    return EXIT_SUCCESS;
}
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