Solidity

Question 1

What is Solidity?

Answer 1

Solidity is a contract driven, object-oriented, high level language to write smart contracts. It’s inspired by C++, Python & JS and runs on Ethereum Virtual Machine (EVM).

It’s a static typed language and supports inheritance, libraries and complex user-defined types.

https://docs.soliditylang.org/

Question 2

What’s the basic syntax of a solidity contract?

Answer 2

pragma solidity VERSION_HERE;

contract CONTRACT_NAME {

}

Question 3

What is the basic syntax of a function in solidity?

Answer 3

function FUNCTION_NAME() public returns(DATA_TYPE memory) {

}

Question 4

Which keyword is used if a function is not changing any data in solidity?

Answer 4

view is used to ensure that a function won’t change any value e.g.

function get() public view returns(string memory) {
     return "test";
}

Question 5

What’s the syntax of constructor in solidity?

Answer 5

constructor() public {

}

Question 6

How to define constants in solidity?

Answer 6

By using constant keyword e.g. string public constant value = “my value”;

Question 7

What are some other basic datatypes in solidity?

Answer 7

boolean as bool, integer as int, unsigned integer as uint, unsigned 8 int as uint8, unsigned 256 int as uint256

Question 8

How to create an enum in solidity?

Answer 8

enum State { Waiting, Running, Active }

Question 9

How to create structs in solidity?

Answer 9

struct Person {
string firstName;
string lastName;
}

Question 10

How to create an array in solidity?

Answer 10

DATA_TYPE[] public NAME; e.g. Person[] public people;

Question 11

How to add an item in array in solidity?

Answer 11

array. push(DATA_HERE);
e. g.
people. push(Person(“Shakeel”, “Shahzad”));

Question 12

How to create an associate array in solidity?

Answer 12

mapping(DATA_TYPE => VALUE) public NAME;

e.g.

mapping(uint => Person) public people;
people[1] = Person(“Shakeel”, “Shahzad”);