HelloWorld.sol

HelloWorld.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract HelloWorld {
    // Declare a public field of type string.
    string public greeting;

    // Constructor to initialize the greeting.
    // In Solidity, the constructor is defined with the "constructor" keyword.
    constructor() {
        greeting = "Hello, World!";
    }

    // Public function to change the greeting.
    // The "public" keyword makes the function accessible from outside the contract.
    function changeGreeting(string memory newGreeting) public {
        greeting = newGreeting;
    }

    // Public function that returns the greeting.
    // In Solidity, explicit return types are declared.
    function hello() public view returns (string memory) {
        return greeting;
    }
}