Most frequently Asked Ethereum Interview Questions

What is Ethereum?
What are some Real-World Applications of Ethereum?
What are the features of Ethereum?
What is Solidity in Ethereum?
How can we Developing MyContract?
What is Cryptography?
What is dApps?
Name some Types of Ethereum Networks?
What is Metamask?
What languages are used to write Smart Contracts?
What is an Ethereum Client?
What is Truffle?
How can we return mapping list in Solidity?

What is Ethereum?

Ethereum is used for allowing the users to build Decentralised Applications such as Bitcoin. Ethereum is an open-source that works through a public Blockchain Network, bitcoin is used in tracking the ownership of the currency. Ethereum Blockchain is used in running the programming code for any decentralized application.
Ethereum also acts as an operating system that consists of key features like:
Virtual Machine,
Transaction-based Sate Transactions,
Smart Contracts.

What are some Real-World Applications of Ethereum?

What are the features of Ethereum?

Features of Ethereum are as follows:

Ether - Ether is Ethereums Cryptocurrency.
Smart Contracts - Ethereum helps in allowing the Development and Deployment of the following.
Ethereum Virtual Machine - Ethereum is used for providing Underlying Technology architecture and Software which can understand and allows us to interacts with Smart Contracts.
Decentralized Applications - Ethereum can allow us for creating Consolidated Application which are known as Decentralized Applications.
Decentralized Autonomous Organizations - Ethereum allows us for creating Democratic Decision Making.

How can we Developing MyContract?

We can create MyContract by using the following command:

Contract MyContract {

We can also declare it by using 2 variables:

unit amount;
unit value;

What is Solidity in Ethereum?

Solidity is a language which is developed for Contract Writing, it is a high level language that can inherit traits by Python, JavaScript and C++.
Solidity Compiler is used for compiling our source code into bytecode which helps in running on Ethereum Virtual Machine.Here is an example of Solidity Syntax:

pragma solidity >=0.3.00 <0.8.0;
contract Ballot {

What is Cryptography?

Cryptography is used by Blockchain for securing the user's identity and ensuring all the transactions are done safely with a hash function. Cryptography also uses Private and Public keys to encrypt and decrypt all the data.
Public Key is shared by all the Bitcoin users but Private Key is kept as a secret by all the users.

What is dApps?

Decentralized Applications(dApps) are digital applications that runs on a blockchain or P2P Network of the computers.They offer many features like open source and many more, it also follows incentivizes and protocol nodes which takes part in functioning of dApp.
dApps can also be used on a Blockchain Network such as BitTorrent, Tor and Popcorn Time are Applications that run on computers which are also a part of P2P Network.

Name some Types of Ethereum Networks?

What is Metamask?

MetaMask is used for interacting with Ethereum Blockchain. It also allows the users to access Ethereum Wallet by using the browser extension, it is also used for interacting with Decentralized Applications.

What languages are used to write Smart Contracts?

Languages used to write Smart Contracts are:
Solidity
Serpent
Viper
Bamboo

What is an Ethereum Client?

Ethereum Client acts as an implementation of Ethereum Protocol.Running Client is known as Node, that is able to parse and for verifying the Blockchain.It also helps in providing an Interface for creating Transactions and Mine Blocks which is the Key for Blockchain Interaction.

What is Truffle?

Truffle is Development and Testing Environment used for Ethereum. It is also used for offering Asset Pipeline, which allows us for handling Ethereum based projects. A developer can also create dApps, Smart Contracts, COnfiguring and Building Pipelines, etc. It is also a perfect framework for developers who uses Ethereum.

How can we return mapping list in Solidity?

We can return Mapping List by using the following command:

contract lister {
    mapping(int => string) list;
    int id = 0;

    function getList() returns ( /*HERE*/ ) {
        return list;
    }

    function setItemToList(string str) {
        list[id] = str;
        id++;
    }
}