https://github.com/StephenGrider/EthereumCasts http://web.archive.org/web/20131228111141/http://vbuterin.com/ethereum.html blockchain with anders: https://anders.com/blockchain/blockchain.html remix.ethereum.org https://github.com/settings/tokens https://iancoleman.io/bip39/ //to restore the account https://infura.io //access to ethereum network https://ethereum.stackexchange.com/a/47654. https://rinkeby.etherscan.io/ //where you want to see you contract deploy on rinkeby

ERROR: - The contract code couldn't be stored, please check your gas limit. Solution: //keep in mind to put '0x' as prefix of the bytecode .deploy({ data: '0x' + bytecode,
arguments: ['initial-message-1'], })

1. Ethereum Network

2. Node: Ethereum of too many nodes each node contains a full copy of the blockchain

3. Web3.js

   • a library: store contract transact moneny

4. Metamask/ Mist Browser extention:

   • allow users non-develpor to use ethereum.
   • install: browse web store/ search for metamask, add extention
   • Create new account
     • account address:
     • public key:
     • private key: //one account can work with all other networks, including the main network
   • http://rinkeby-faucet.com/: //to receive token

5. Rinkeby Test network

6. How transction works: step 1: submit Step 2: account address sent to the backend server Step 3: Backend server used web3 library to create a transaction object (see 7) Step 4: Backen server sent transaction object to the Rinkeby test network (or main network) Step 5: Backen server wait for transaction to be confirmed Step 6: Backen server sent seccuss message back to the browser (user)

7. Transaction:

   • nonce: number of times the sender has sent a transaction
   • to: address of the ongoing receiver
   • value: the amount of ethereum the sender going to send
   • gasPrice: amount of ethereum the sender is going to pay per unit gas
   • startGas/gasLimit: Units of gas that this transaction can consume
   • v, r, s: cryptographic picies of data that can be used to generate the sender's account address //these number were generated from sender's private key (one way generated)

8. Blockchain:

   • block number: it is a number of a chain of block
   • nonce: nonce + data -> hash = a hex value that < a target
   • target: or difficulty: a number predefined. the smaler, the target, the harder the finding
     • target block time:
   • block time: time to run all the hash posibilities to get the target.

9. smart contract

   • concept:
   • contract account:
     • balance: ethereum currently in the account
     • starage: Data storage for this contract
     • code: Raw machine code for this contract

10. Solidity.

    • Strong typed

    • file extention: .sol

    • gotchas.

    • Solidity compiler:

      • byte code ready for deployment
      • application binrary interface (ABI)

    • Remix: //first pecies of code pragma solidity ^0.4.17; contract Inbox { string public message;

            constructor (string initialMessage) public {
                message = initialMessage;
            }
            
            // function Inbox(string initialMessage) public {
            //     message = initialMessage;
            // }
            
            function setMessage(string newMessage) public {
                message  = newMessage;
            }
            
            function getMessage() public view returns (string) {
                return message;
            }
        }
      

    • function type:

      • public: any one can access
      • private: only the class itself can call the function
      • view: this type of function used to return data, does not monify contract's data
      • constant: means the same as view
      • pure: not really usefull
      • payable: send ethereum.

    • Run:

      • environment: javascript VM
      • account
      • Gas limit
      • Value

    • Deploy: //Create an instance of the contract

    • submit the transaction: //when we want to change anything on blockchain.

11. Get more Ether

    • https://faucet.rinkeby.io/
    • plus.google.com //create new port with content = your ether account //copy the post link and paste on https://faucet.rinkeby.io/ //request ether amount

12. Truffle

    • troulbe expecting: not runing, not stable since it is rapid developing
    • contract creation
    • local Testing
    • Development //

13. solidity compileter

    • install npm install --save solc

14. Visual Studio C++

    • install: npm install --global --production windows-build-tools

15. Test library

    • install npm install --save mocha ganache-cli web3
    • Mocha: //general purpose for testing javascript whether front-end or backend.
      • it: run a test and make an assertion.
      • describe: groups together "it" functions
      • beforeEach: execute some general setup code.
    • scripts for using mocha to test: "scripts": { "test": "mocha" },
    • run the test: npm run test

16. Truffle

    • install npm install --save truffle-hdwallet-provider

17. Balance of contract:

    • using: const balance = await web3.eth.getBalance(accounts[0]);