Ethereum Cookbook

How to do it...

Follow these steps to write your "hello world" contract:

1. Specify the target compiler version using version pragma. It is recommended to specify the target compiler version for each contract. This will avoid the contract getting compiled on future or older versions, which might have incompatible changes:

    pragma solidity ^0.4.21;

This source code will not compile with a compiler with a version lower than 0.4.21 or greater than 0.5.0.

2. Create a contract with the contract keyword followed by the contract name:

 contract HelloWorld {     // Here goes your smart contract code }

3. Write a method that we can use for printing "hello world." The method declaration starts with the function keyword:

function printSomething() { // things ...