CBDE 試験問題を無料オンラインアクセス

A Private Network is:

• A.a Network running only in a private area, where people cannot join freely and openly.
• B.an exact clone of the Rinkeby Test-Network which can be started as virtual machine in the Azure Cloud.
• C.a side Channel to the Ethereum Main Net which costs less gas to run smart contracts.

The following are value types in Solidity.

• A.Integer, Boolean, Struct, Mapping and Enum.
• B.Integer, Boolean, Enum and Addresses.
• C.Integer, Boolean, Structs and Fixed Point Numbers.

Function and Variable Visibility:

• A.a function that is marked as external can never be called internally. Private functions can also be called by derived contracts using inheritance. Private variables are accessible also in derived contracts.
• B.a function that is marked as internal cannot be called by other contracts, unless the function is used by a derived contract. Private Functions cannot be called by any other outside contract and public variables are generating automatically a getter function.

If contract MyContractA is derived from Contract MyContractB, then this would be the right syntax:

• A.contract MyContractA is MyContractB { ... }
• B.contract MyContractA extends MyContractB {...}
• C.contract MyContractB derives MyContractA {...}
• D.contract MyContractA inherit (MyContractB) {...}

You interact with a smart contract and see a gas usage of 50,000 gas with a gas cost of 15Gwei.
How much Ether would you have to pay to the miner?

• A.A flat fee of 1 Ether
• B.750,000,000 Wei
• C.750,000,000,000,000 Wei
• D.750,000,000,000 Wei