Example of a Counter with Owner access control in Solidity (for a blog post)

CounterOnlyOnwer.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

contract Counter {
    uint public count;
    address owner;
    
    // Modifier that makes sure the caller is the owner
    modifier onlyOwner() {
      require(msg.sender == owner);
      _;
    }

    // Constructor that sets the owner as the initial creator of the smart contract
    constructor() {
      owner = msg.sender;   
    }

    // Function to get the current count
    function get() public view returns (uint) {
        return count;
    }

    // Function to increment count by 1
    function inc() public {
        count += 1;
    }

    // Function to decrement count by 1, method only accessible by the owner
    function dec() public onlyOwner {
        // This function will fail if count = 0
        count -= 1;
    }
}