ym705

Yes the block chain is by definition immutable. So no means to update the contract the only way if it is a ENORMOUS mistake would be to fork it: read about DAO hack FYI

No the smart contract is on the blockchain and executed by the nodes. Never on your specific host alone

Yep that is why there is a notice and link about random number generation in the tutorial.

Have you read next article? https://ethereumdev.io/better-readability-with-modifiers/

Could you explain more how would it be possible?

I dream about blockchains. Yeah it's true, not only the technology is interesting but also the community and all the ecosystem behind cryptocurrencies.

Uses case are infinite.. You could also for example write transparent casinos system, transparent marketplace where every transactions would be certified by both parts, a banking system, some new money, ect..

"To me it sounds like it is much smarter to use some pre-existing smart contract which is used by many, instead of making your own." This is exactly how the last "big hacking" had happened https://qz.com/1034321/ethereum-hack-a-coding-error-led-to-3...

But as you said writing your own is also error prone.

They are frameworks for supporting development with testing (not covered it yet) for example http://truffleframework.com/

Nice design. I did similar game for Android https://play.google.com/store/apps/details?id=com.ym705.geo&...

They are so silent that I thought I did not have neighbors..

Thanks! I guess you are japanese, what did you think about the post?