Struct writing (memory vs. storage) comparison.

Storage.sol

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

contract Storage {
    struct SomeStruct {
        uint16 a;
        uint16 b; 
        uint16 c;
        uint16 d;
    }

    SomeStruct private _s;
    
    // gas: 2474 (write to memory, then write to storage)
    function writeStructMemory(uint16 a, uint16 b, uint16 c, uint16 d) public returns (uint256 gasUsed) {
        uint256 startGas = gasleft();
        SomeStruct memory s = SomeStruct({a: a, b: b, c: c, d: d});
        _s = s;
        gasUsed = startGas - gasleft();
    }

    // gas: 2351 (with storage pointer)
    function writeStructStorage(uint16 a, uint16 b, uint16 c, uint16 d) public returns (uint256 gasUsed) {
        uint256 startGas = gasleft();
        SomeStruct storage s = _s;
        s.a = a;
        s.b = b;
        s.c = c; 
        s.d = d;
        gasUsed = startGas - gasleft();
    }

    function readStruct() public view returns (SomeStruct memory) {
        return _s;
    }
}