Smart Contract: HelloWorld

安裝IDE

brew tap ethereum/ethereum

brew install cpp-ethereum
brew linkapps cpp-ethereum

#或安裝測試版及圖形界面
brew reinstall cpp-ethereum --devel --with-gui
brew linkapps cpp-ethereum

#you can then find AlethZero and Mix in your Applications folder

更多安裝詳情步驟

使用Solidity

• Solidity Documentation - Solidity is the flagship Ethereum high level language that is used to write contracts.
• Solidity online realtime compiler
• Standardized Contract APIs
• Useful Ðapp Patterns - Code snippets which are useful for Ðapp development.

contract HelloWorld {
        event Print(string out);
        function() { Print("Hello, World!"); }
}

編譯

Compiling a contract

Compilation of solidity contracts can be accomplished via a number of mechanisms.

• Using the solc compiler via the command line.
• Using web3.eth.compile.solidity in the javascript console provided by geth or eth (This still requires the solc compiler to be installed).
• The online Solidity realtime compiler.
• The Meteor dapp Cosmo for building solidity contracts.
• The Mix IDE.
• The Ethereum Wallet.

The compiler is also available via RPC and therefore via web3.js to any in-browser Ðapp connecting to geth via RPC/IPC.如

$ geth --datadir ~/eth/ --loglevel 6 --logtostderr=true --rpc --rpcport 8100 --rpccorsdomain '*' --mine console  2>> ~/eth/eth.log
$ curl -X POST --data '{"jsonrpc":"2.0","method":"eth_compileSolidity","params":["contract test { function multiply(uint a) returns(uint d) { return a * 7; } }"],"id":1}' http://127.0.0.1:8100

佈署一個contract

var primaryAddress = eth.accounts[0]
var abi = [{ constant: false, inputs: { name: 'a', type: 'uint256' } ]
var MyContract = eth.contract(abi)
var contract = MyContract.new(arg1, arg2, ..., {from: primaryAddress, data: evmByteCodeFromPreviousSection})

contract的操做

更多請詳細操做參考

Web3 base service layer