Figure 5 .9 : ReMix IDE Screen

The remix user interface

You can choose between Solidity and Vyperin the U I, both of which are

used for writing smart contracts and their programs compiled to the EVM

bytecode. Our choice is Solidity; there are .sol files on the left-hand side’s

File Explorer window; to demo the basic syntax, the file ballot.sol is

smart contract and ballot_test.sol is the script used for testing that smart

contract, Select create a new file and give the file name.

The methodology of version compatibility

All solidity source code starts with a declaration of the version of the

Solidity compiler “version pragma”, this code should use the methodology

for version compatibility, which prevents issues with future compiler

versions which may potentially introduce changes that would break your

code, pragma solidity ^ 0.4.25 ; (Solidity version above 0.4.25 ), and pragma

solidity ≥ 0.5 .0 < 0.6.0 (Solidity version between 0.5 .0 and 0.6.0).

Solidity environment setup

You can use the online compiler for contracts if you do not have a Linux

machine. The Solidity compiler can be set up on CentOS machines using

these methods.

1. npm / node.js

Install node.j s

$sudo yum install epel-release

$sudo yum install nodejs