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 34 35 36 37 38 39 40 41 42 43 44 45 46 | #include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
union IntOrString {
char* as_string;
int as_int;
};
enum IntOrStringType {
TYPE_STRING,
TYPE_INT
};
// struct fields can be any type,
// including union, enum, and other structs
struct IntOrStringStruct {
union IntOrString ios;
enum IntOrStringType type;
};
// simplifies parameter, just passing one element
void print_int_or_string(struct IntOrStringStruct ioss) {
if (ioss.type == TYPE_STRING) {
printf("ios.as_string == %s\n", ioss.ios.as_string);
} else if (ioss.type == TYPE_INT) {
printf("ios.as_int == %d\n", ioss.ios.as_int);
}
}
int main(int argc, char* argv[]) {
struct IntOrStringStruct five = {
.ios.as_int = 5,
.type = TYPE_INT
};
print_int_or_string(five);
five.ios.as_string = "five";
five.type = TYPE_STRING;
print_int_or_string(five);
return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */
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