Why does this compile and why is the answer zero?

Question

https://code.sololearn.com/cb8pkbJHVsoI/?ref=app

Answer 1

Federico 🐺 thanks for the links.

Answer 2

Federico 🐺 in real life I would have never written such code if not for a challenge question I encountered here? See below.

https://www.sololearn.com/post/179198/?ref=app

Answer 3

I'm especially surprised that line 6 does not cause an error.

Answer 4

My guess is that it’s probably getting 0 as the value of whatever was stored in the memory address located just before the array. C++ doesn’t seem to care about where its arrays are being indexed at lol

Answer 5

Becuz you can't put -1