Solidity basics

Write your first contract.

📖 Key ideas

Start with SPDX licence and pragma solidity ^0.8.x;
contract Counter { uint256 public count; function increment() public { count += 1; } }
Types: uint256, int, bool, address, string, bytes.
Visibility: public, external, internal, private.
Solidity 0.8+ checks arithmetic overflow automatically.

💡 Real-life example: A contract is a class whose state lives forever on the blockchain.

pragmaCompiler version directive

uint256Unsigned 256-bit integer

addressEthereum account type

publicVisible to everyone, auto getter