solidity语言9
输入参数
pragma solidity ^0.4.16;
contract Simple {
function taker(uint _a, uint _b) public pure {
// do something with _a and _b.
}
}
输出参数
pragma solidity ^0.4.16;
contract Simple {
function arithmetics(uint _a, uint _b) public pure returns (uint o_sum, uint o_product) {
o_sum = _a + _b;
o_product = _a * _b;
}
}
关键字returns，返回参数如果没有，则返回0
返回多个值
return (v0, v1, ..., vn)，函数的输出参数必须匹配同样数量参数
内部函数调用
pragma solidity ^0.4.16;
contract C {
function g(uint a) public pure returns (uint ret) { return f(); }
function f() internal pure returns (uint ret) { return g(7) + f(); }
}
外部函数调用
表达式 this.g(8)， c.g(2)
当调用其他合约的函数，调用的转帐wei，gas使用.value() 和 .gas()
pragma solidity ^0.4.0;
contract InfoFeed {
function info() public payable returns (uint ret) { return 42; }
}
contract Consumer {
InfoFeed feed;
function setFeed(address addr) public { feed = InfoFeed(addr); }
function callFeed() public { feed.info.value(10).gas(800)(); }
}
info函数必须使用payable修饰符
通过new建立合约
合约使用关键字new创建新合约
pragma solidity ^0.4.0;
contract D {
uint x;
function D(uint a) public payable {
x = a;
}
}
contract C {
D d = new D(4); // will be executed as part of C's constructor
function createD(uint arg) public {
D newD = new D(arg);
}
function createAndEndowD(uint arg, uint amount) public payable {
// Send ether along with the creation
D newD = (new D).value(amount)(arg);
}
}
posted on
2018-02-28 14:48
北京涛子 阅读(
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转载于:https://www.cnblogs.com/liujitao79/p/8483583.html
