ReasonJun

An event in Solidity is a way to log and notify external entities (such as user interfaces or other smart contracts) about specific occurrences within a smart contract. Events are similar to logs or records that capture important information, allowing external observers to react to them and obtain relevant data. Events are defined using the event keyword, followed by the name of the event and th..

// SPDX-License-Identifier: MIT pragma solidity >= 0.7.0 < 0.9.0; contract Array { uint[] public arr; uint[] public arr2 = [1, 2, 3]; uint[10] public myFixedSizeArr; // 0 function get(uint i) public view returns (uint) { return arr[i]; } function get() public view returns (uint[] memory) { return arr; } function push(uint i) public { arr.push(i); } function pop() public { arr.pop(); } function g..

Memory and calldata are two different data locations in Solidity. Memory is used to store temporary data during the execution of a function, while calldata is used to store function arguments. Memory Memory is a temporary data location that is used to store data during the execution of a function. When a function is called, memory is allocated for the function call and all local variables in the..

A mapping in Solidity is a data structure that stores key-value pairs. The key can be of any built-in data type, except reference types, and the value can be of any type, including mappings, arrays, and structs. Mappings are similar to dictionaries in other programming languages. They are often used to store data that needs to be accessed quickly and easily, such as user accounts, balances, and ..

Keccak256 is a cryptographic hash function that takes an input of any length and produces a fixed-length output of 256 bits. It is a one-way function, which means that it is easy to compute the hash of an input but very difficult to reverse the hash and find the original input. Keccak256 is used in a variety of cryptographic applications, including digital signatures, message authentication code..

Events and emit are two important concepts in Solidity. Events are a way to log and notify external entities (such as user interfaces or other smart contracts) about specific occurrences within a smart contract. Emit is the keyword used to trigger or emit events within the smart contract code. Events are similar to logs or records that capture important information, allowing external observers t..