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以太坊智能合约solidity

https://ethereum.github.io/browser-solidity/#version=soljson-v0.4.13+commit.fb4cb1a.js (solidity 在线IDE)

solidity 语言类型及示例solidity

  1. int/uint 数组类型的定义:
    • uint[] array;
    • int[] array;
    • 数组类型的成员有两个: push 和 length
      • push 给数组类型增加一个元素, 同时该数组长度加1;
      • length 返回当前的数组长度。
contract Demo{
    uint[] public array
    function testDemo(uint a) returns (uint lenth){
        array.push(a);
        return array.length;    
    }
}



2. 数组的增删改查:

contract ArrayOperation{
    uint[] public array;
     //数组添加元素
    function add(uint a) returns (uint result){
        array.push(a);
    }
    //获取数组下标元素值
    function valueOf(uint index) returns (uint value){
        if(index >= array.length)   throw;
        return array[index];
    }
    //更新元素
    function updata(uint index, uint value){
        if(index >= array.length)   throw;
        array[index] = value;
    }
    //删除元素
    function delete(uint index){
        uint len = array.length
        if(index >= len )   throw;
        for(uint i = index; i < len - 1; i++){
            array[index] = array[index + 1]
        }
        delete (array[len - 1]);
        array.length --;
    }
}



3. 简单模拟代币合约, 包含(转账, 挖矿, 构造):

pragma solidity ^0.4.0;
contract Token{
    uint[] public balanceOf;
    //初始化两个模拟账户
    function Token(){
        balanceOf.push(4500);
        balanceOf.push(1000);
    }
    //两个账户进行转账
    function transfer(uint _from, uint _to, uint amount){
        if(_from >= balanceOf.length || _to >= balanceOf.length || _from == _to )   return;
        if(balanceOf[_from] < amount)   return;
        balanceOf[_from] -= amount;
        balanceOf[_to] += amount;
    }
    //挖矿,所有的收入都放入第一个账户中
    function mint(uint amount){
        balanceOf[0] += amount;
    }
}



4. address, mapping 类型的使用:
* 1 mapping的使用, 一般键为地址, 值为余额 mapping(address => uint);
* 2 address : 以太坊账户地址;
* 3 address: Holds a 20 byte value (size of an Ethereum address). Address types also have members and serve as base for all contracts.
* 4 address 含有两个成员, balance 和 send;




5. 合约账户中 msg 的定义
* 1 msg 指谁调用该智能合约发来的信息。 注意:智能合约也是一个账户
* 2 msg 包含的成员:
* msg.data(bytes): 获取调用者传入的数据信息
* msg.gas(uint): 剩余的以太币
* msg.sender(address): 当前调用者的以太坊账户地址
* msg.sig(bytes4): first four bytes of cakkData
* msg.value(uint): number of wei sent with the message;注意: 只有当有以太坊币的转义时, 该变量才有值(除调用合约所花费以太币这种情况)

pragma solidity ^0.4.0;

contract  Token{
    mapping (address => uint) public balanceOf;
    address public owner;
    event Sent(address sender, address receiver, uint amount); //定义一个时间

    //获取部署合约的账户地址, 并初始化该地址的余额
    function Token(){
        owner = msg.sender;
        balanceOf[owner] = 10000;
    }
    //账户地址交易
    function transfer(address _to, uint amount){
        if(balanceOf[msg.sender] < amount)     throw;  //进行判断,防止发送账户的余额不足
        if(balanceOf[_to] + amount < balanceOf[_to])   throw;  //防止自己给自己转账,或递归调用(因为每次调用都有额外的花费) 
        balanceOf[_to] += amount;
        balanceOf[msg.sender] -= amount;
        Sent(msg.sender,  _to, amount);   ///调用事件
    }

    //挖矿
    function mint(uint amount){
         balanceOf[owner] += amount;
    }


}



6. enum 类型

contract Demo{

    enum ActionCode{ Left, Right, down}

    ActionCode public enumType;

    function Demo(){
        enumType = ActionCode.Left;
    }

    function Left(){
        enumType = ActionCode.Left;
    }

    function Right(){
        enumType = ActionCode.Right;
    }

    function Down(){
        enumType = ActionCode.down;
    }

    function f() returns(string str){
        if(enumType == ActionCode.Left)     return "Left";
        if(enumType == ActionCode.Right)    return "Right";
        if(enumType == ActionCode.down)     return "down";
    }
}



7. struct 类型

contract DemoStruct{
    struct Person{
        uint age;
        string name;
        uint sexy;
        string phone;
    }

    Person[] public PersonLists;

    function DemoStruct(){
        uint id = PersonLists.length++;
        Person p = PersonLists[id];
        p.age = 20;
        p.sexy = 0;
        p.name = "wukong";
        p.phone = "1235432328";
    }


    function addPerson(uint age, uint sexy, string name, string phone){
        uint id =  PersonLists.length++;
        Person p = PersonLists[id];
        p.age = age;
        p.sexy = sexy;
        p.name = name;
        p.phone = phone;
    }
    function addPersontwo(uint _age, uint _sexy, string _name, string _phone){
        uint id =  PersonLists.length++;
        PersonLists[id] = Person({age: _age, name: _name, sexy: _sexy, phone: _phone});
    }
}



8. 以太坊中的数据单位
* ether
* finney
* szabo
* wei
* 1 ether = 1 * 10^18 wei;
* 1 ether = 1 * 10^6 szabo;
* 1 ehter = 1* 10^3 finney;



9. 时间类型
* seconds
* minutes
* hours
* days
* weeks
* years
* now



10. mapping 类型

参考博客

  1. 以太中文网
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