void printf(char*, ...);

int fibonacci(int n) {
    if (n < 2)
        return 1;
    return fibonacci(n - 1) + fibonacci(n - 2);
}

void change_first(const char* otus) {
    otus[0] = 115;
}


struct Otus;

void update(struct Otus potus) {
    potus.field = 20;
}
struct Otus {
    int field;
};

void update_ptr(char* ptr) {
    *ptr = 50;
}

int main() {
    char text[29] = "10th fibonacci number is %d!";
    printf(text, fibonacci(10));

    char somelist[5] = { 1, 2, 3, 4, 5 };

    change_first(somelist);

    printf(" first element: %d!", somelist[0]);

    struct Otus otus = { 5 };
    update(otus);

    printf(" first field: %d!", otus.field);

    char hello = 10;
    update_ptr(&hello);
    printf(" hello: %d!", hello);

    return 0;
}