CBDE BTA Certified Blockchain Developer - Ethereum Questions and Answers

great, because they cut the middle man, run on a trusted platform, apply logic to the blockchain where already economic assets are running and thus allow peer to peer trade.

an amazing way to create new applications. Those applications run entirely separated from other applications on the platform and allow for logical interactions. They can't access any funds to add an additional layer of trust.

a new way of applying logical operations for banks and big financial institutions. This way they can reduce the staff while operating at increased security.

everybody can become a miner, everybody can send transactions and everything is public.

usually only a few selected nodes can be miners. Transactions can be further limited.

While the EVM is Sandboxed, it isn't as powerful as the Bitcoin Network, because it's not Turing Complete.

The EVM can't access hardware layers or anything outside a blockchain node because it's sandboxed.

The EVM is extremely powerful, turing complete and perfect for doing computational intensive things, because of the direct access to the graphics card.

its best to use a contract with public storage variables, so it can be used like a class.

it's best to use a struct, which is cheaper than deploying a new contract.

it's not possible to generate new datatypes in Solidity.

to run tests quickly and especially for free, compared to continuous deployment on the MainNetwork. This way you save a lot of fees, time and costs.

to run tests in an environment where logging is activated. On the Main-Net you have no access to transaction logs and this is ultimately the information you need to debug your contracts.

to avoid regression bugs with contracts that are updated constantly on the main-net. Once you update a contract on the main-net, the address stays the same, but the code changes and this can have disastrous side-effects.

is a must for every developer, because Web3.js changes so often.

is a convenient way because Web3.js is currently still in beta and truffle-contract can handle transactions with JavaScript-promises.

they are both completely different things. Truffle-Contract is a framework while Web3.js is a library.

the library you use must make use of the JSON-RPC Interface of an Ethereum Node.

must Implement the Ethereum Protocol to connect to other Ethereum Nodes.

must use Web3.js, which is closed source to communicate to other Ethereum Nodes.

Wei, Finney, Szabo, Ether, Tether.

Finney, Szabo, Mether, Gwei.

Gwei, Szabo, Finney, Ether.

would be better, because it can reduce the amount of energy needed for mining.

would be worse, because it would increase the amount of energy needed for mining.

it's good to inform users about the updates via a newsletter.

it's good to have the ability to pause a contract in order to manage the money at risk.

Ethereum doesn't upgrade the platform. It's fixed and final.

with private state variables. This way nobody else other than the smart contract itself can see the information

with external contracts holding those values. This way we can make sure that the information flow is following a clear logic and nobody else can access this information.

You can't hide anything on the blockchain, because the information is public, just the call is private which means only other smart contracts would be limited in accessing that information.

a function marked as pure can change the state, while a view function can only return static calls.

a function marked as view can never access state variables, while pure functions are here to return only one value.

a view function can access state variables, but not write to them. A Pure function cannot modify or read from state.