void printf(char*, ...);

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

void change_first(char otus[5]) {
    otus[0] = 115;
}


struct Otus;

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

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

int main() {
    char text[30] = "10th fibonacci number is %d!\n";
    printf(text, fibonacci(10));

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

    change_first(somelist);

    printf("first element: %d!\n", somelist[0]);
    printf("first element via ptr: %d!\n", somelist_ptr[0]);

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

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

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

    return 0;
}