Notes

• To write or update a state variable you need to send a transaction.
• On the other hand, you can read state variables, for free, without any transaction fee.

Code

solidity
SimpleStorage.sol
Copy
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract SimpleStorage {
   // State variable to store a number
   uint public num;

   // You need to send a transaction to write to a state variable.
   function set(uint _num) public {
       num = _num;
   }

   // You can read from a state variable without sending a transaction.
   function get() public view returns (uint) {
       return num;
   }
}