Just a simple script that tests gas usage in remix

Gas.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.0;

contract Gas {

    uint public c = 1;

    function notOptimized() external returns(uint gasUsed){        
        uint startGas = gasleft();
        c++;
        gasUsed = startGas - gasleft();
    }

    function optimized() external returns(uint gasUsed){        
        uint startGas = gasleft();
        ++c;
        gasUsed = startGas - gasleft();
    }    
}
// 5161
// 5167