Pass the Blockchain Blockchain Developer - Ethereum CBDE Questions and answers with CertsForce

is great, because they often find bugs which weren't considered before.

is not good, because you might give out secrets.

it’s good to use a push over a pull method.

it’s good to use a push and a pull method to ensure that participants can get their money no matter the contract state. In addition to and pushing it should contain a withdraw method.

it's good to use only pull and no push method.

it always produces the same output given the same input.

it uses equally distributed data to produce the output given a long input.

it shouldn't be possible to re-generate the input given the output.

the amount of gas your contract deployment and transactions, against your contract, will need. This way you can essentially lower the gas costs over traditional web3.js dApps.

different Networks to deploy your contracts to. This way you can easily deploy to a local blockchain, the main-net or the Ropsten/Rinkeby Test-Net with only one parameter.

you can manage your secret API keys to the Ethereum Network. This way you can get access to several different Ethereum nodes at the same time without the need to switch your keyfiles.

to Wei, so it will send the equivalent of 10^18 Wei.

to Finney, so it will send the equivalent of 10^3 Finney.

to Szabo, so it will send the equivalent of 10^6 Szabo.

to use it for the whole business logic. It’s always best to have everything in once place.

to use it only for things which need the benefits of the blockchain.

all public state variables and properties, public and internal functions and modifiers.

all public and private state variables, public, internal and external functions, but not modifiers

all public state variables and properties, public functions and modifiers, but not internal, external or private ones.

string1 == string2

the internal function "str_compare(str1,str2)"

you can't directly compare two strings, but one method would be to hash both strings and compare the hashes.

bytes32(string1) == bytes32(string2)

you should follow the checks-effects-interactions pattern and avoid state changes after the call.

you should follow the effects-checks-interactions pattern and avoid state changes before the call.

you should follow the checks-effects-interactions pattern, which is only necessary when you do calls to contracts where a direct contract call is not possible.

the User.

contract A.