如何在Solidity中连接两个字符串值

pragma solidity ^0.8.0;

contract StringConcatenation {
    function concatenateStrings(string memory str1, string memory str2) public pure returns (string memory) {
        bytes memory str1Bytes = bytes(str1);
        bytes memory str2Bytes = bytes(str2);
        
        bytes memory concatenated = new bytes(str1Bytes.length + str2Bytes.length);
        
        uint256 k = 0;
        for (uint256 i = 0; i < str1Bytes.length; i++) {
            concatenated[k++] = str1Bytes[i];
        }
        
        for (uint256 i = 0; i < str2Bytes.length; i++) {
            concatenated[k++] = str2Bytes[i];
        }
        
        return string(concatenated);
    }
}