Solidity completed part 11, Solidity basics now complete

### Part 11 video link

<https://www.youtube.com/watch?v=SPeKei4K-18>

### Part 11 related .sol files

### Part 11 notes

- [MyContractCalls.sol](./contracts/MyContractCalls.sol)

- [MyInport.sol](./contracts/MyImport.sol)

### Part 11 notes

- course covers imports from web or other local .sol files

- instead of declaring a variable with `string` you could declare it with `bytes32` instead

  - this uses less gas than strings

  - strings are essentially just bytes

- there is a way to convert any data into a hash

  - in Solidity, the hashing algorithm used is Keccak256

- why is this important? it helps with validation

  - this is like what they do with passwords on normal databases

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

// contract deployed @ 0x599DB3Ffbba36FfaAB3f86e92e1fCA0465b2CDeA

contract MyOtherContract {

    uint256 public age = 29;

    function getAge() public view returns (uint256) {

        return age;

    }

}

contract MyContractCalls {

    function getAgeFromOtherContract(address _otherContractAddress) public view returns (uint256) {

        MyOtherContract other = MyOtherContract(_otherContractAddress);

        uint256 age = other.getAge();

        return age;

    }

}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.20;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol";

import "./MyLoop.sol";

contract NFT {

    string name;

    uint256 dna;

    constructor(string memory _name, uint256 _dna) {

        name = _name;

        dna = _dna;

    }

}

contract MyImport is ERC721, MyLoop {

    NFT[] public nfts; // NFT type must be either imported or declared in same file

    string myName = "Chris";

    bytes32 myBytesName = "Chris"; // this is supported, and sometimes it's better to use bytes32 to declare strings than strings themselves

    // bytes take less gas than strings do

    constructor(string memory _name, string memory _symbol) ERC721(_name, _symbol) {}

    function addNFT(string memory _name, uint256 _dna) public {

        NFT nft = new NFT(_name, _dna);

        nfts.push(nft);

    }

    function myHashedName(string memory _name) public pure returns (bytes32) {

        return keccak256(abi.encodePacked(_name));

    }

}