Solidity智能合约调用智能合约

来源：https://medium.com/@blockchain101/calling-the-function-of-another-contract-in-solidity-f9edfa921f4c

合约一：

pragma solidity ^0.4.;
contract Deployed {
    uint public a = ;

    function setA(uint _a) public returns (uint) {
        a = _a;
        return a;
    }

}

合约二调用合约一：

pragma solidity ^0.4.;
contract Deployed {

    function setA(uint) public returns (uint) {}

    function a() public pure returns (uint) {}

}
contract Existing  {

    Deployed dc;

    function Existing(address _t) public {
        dc = Deployed(_t);
    }

    function getA() public view returns (uint result) {
        return dc.a();
    }

    function setA(uint _val) public returns (uint result) {
        dc.setA(_val);
        return _val;
    }

}