1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>

// UNION -- using cannonical syntax (not typedef), for now.

union Number {
    int   as_int;
    float as_float;
};   // Do not forget the semicolon at the end of a struct or union type definition!

void print_number(union Number n, bool is_int) {
    if(is_int) {
        printf("n has the value %d\n", n.as_int);
    }
    else {
        printf("n has the value %.08f\n", n.as_float);
        // %.08f → 8 digits to right of decimal point
    }
}

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

    union Number  n = { .as_int = 3 };   // named initializer
    print_number(n, true);

    n.as_float = 3.1415; // This overwrites the bytes in which the int value was stored.
    print_number(n, false);
    
    return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */

© Copyright 2022 Alexander J. Quinn         This content is protected and may not be shared, uploaded, or distributed.