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: */
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