enum.c

// Copyright 2022 Eliot Roxbergh. Licensed under AGPLv3 as per separate LICENSE file
#include <limits.h>
#include <stdio.h>

enum codes {
    DOG,    // 0
    COW,    // 1
    MONKEY  // 2
};

// enum is standard integer type so may be used as such,
//  and any integer may actually be passed to this function
void func(enum codes e) { printf("%d\n", e); }

int main()
{
    int secret_variable = 0;
    func(DOG);
    func(COW);
    func(MONKEY);
    func(1);

    /* NOTE "invalid" numbers may also be passed */
    func(10);        // 10
    func(-1);        // -1
    func(3.3);       // 3 .. will be cast to integer (floored), regular implicit cast
    func(UINT_MAX);  // overflows to -1 (or maybe something else ... signed overflow is undefined behavior in C but
                     // don't worry about it ;) )
    func(UINT_MAX + 1 == 0);  // 0==0 => 1 (true)
    func(secret_variable =
             (DOG));  // assignment is allowed here of course (argument secret_variable is used to the function)

    printf("\n\nDOG %d\n", secret_variable);  // 0

    return 0;
}