Solidity中uint转string

　　在《Solidity中uint转bytes》中，我们知道unit如何转换成bytes，其实把uint转换成string，就是在最后加上string(bytes变量)即可，如下所示：

pragma solidity ^0.4.2;

contract Test {

    function toBytesNickJohnson(uint256 x) constant returns (bytes b) {
        b = new bytes(32);
        assembly { mstore(add(b, 32), x) }
    }

    function getStr(uint playChoice) returns (string s) {
        bytes memory c = toBytesNickJohnson(playChoice);
        return string(c);
    }

    function toBytesEth(uint256 x) constant returns (bytes b) {
        b = new bytes(32);
        for (uint i = 0; i < 32; i++) {
            b[i] = byte(uint8(x / (2**(8*(31 - i)))));
        }
    }

    function toBytesNicolasMassart(uint256 x) constant returns (bytes c) {
        bytes32 b = bytes32(x);
        c = new bytes(32);
        for (uint i=0; i < 32; i++) {
            c[i] = b[i];
        }
    }
}

　　但是呢，我在这里再附加一种Solidity中uint转string方法，如下所示：

pragma solidity ^0.4.2;

contract Test {

    function uint2str(uint i) internal returns (string c) {
        if (i == 0) return "0";
        uint j = i;
        uint length;
        while (j != 0){
            length++;
            j /= 10;
        }
        bytes memory bstr = new bytes(length);
        uint k = length - 1;
        while (i != 0){
            bstr[k--] = byte(48 + i % 10);
            i /= 10;
        }
        c = string(bstr);
    }
}