The Solution given in Convert address to string did not help.

Motive: To convert an address to string type so that I can use it as a parameter to a function for which string type is necessary.

Code Snippet:

function toString(address x) returns (string) {
    bytes memory b = new bytes(20);
    for (uint i = 0; i < 20; i++) {
        b[i] = byte(uint8(uint(x) / (2**(8*(19 - i)))));
    return string(b);

function getResult() constant returns (string) {
    string memory myAddress = toString(msg.sender);
    return myAddress;

Now, when I call getResult() using truffle I get the following error.

Error: Invalid continuation byte
    at Error (native)
    at readContinuationByte (C:\Users\perecept\AppData\Roaming\npm\node_modules\truffle\build\cli.bundled.js:59394:9)
    at decodeSymbol (C:\Users\perecept\AppData\Roaming\npm\node_modules\truffle\build\cli.bundled.js:59423:12)
    at Object.utf8decode [as decode] (C:\Users\perecept\AppData\Roaming\npm\node_modules\truffle\build\cli.bundled.js:59469:33)
    at Object.toUtf8 (C:\Users\perecept\AppData\Roaming\npm\node_modules\truffle\build\cli.bundled.js:5184:17)
    at SolidityTypeString.formatOutputString [as _outputFormatter] (C:\Users\perecept\AppData\Roaming\npm\node_modules\truffle\build\cli.bundled.js:24766:18)
    at C:\Users\perecept\AppData\Roaming\npm\node_modules\truffle\build\cli.bundled.js:28364:25
    at SolidityTypeString.SolidityType.decode (C:\Users\perecept\AppData\Roaming\npm\node_modules\truffle\build\cli.bundled.js:28365:11)
    at C:\Users\perecept\AppData\Roaming\npm\node_modules\truffle\build\cli.bundled.js:59736:29
    at Array.map (native)

Please help understand the root cause of this error as I failed to detect any mistake in my code.

Thank you in advance!

  • Which version of solidity are you using? – R.D Oct 9 '18 at 5:59

As already explained in the second most voted answer, you should try to convert it into an ASCII string. Strings in Solidity are UTF8, so check if the following helps:

function toAsciiString(bytes32 data) public pure returns (string) {
    bytes memory s = new bytes(40);
    for (uint i = 0; i < 20; i++) {
        byte b = byte(uint8(uint(data) / (2**(8*(19 - i)))));
        byte hi = byte(uint8(b) / 16);
        byte lo = byte(uint8(b) - 16 * uint8(hi));
        s[2*i] = char(hi);
        s[2*i+1] = char(lo);            
    return string(s);

function char(byte b) internal pure returns (byte c) {
    if (b < 10) return byte(uint8(b) + 0x30);
    else return byte(uint8(b) + 0x57);

This is right solution:

function addressToString(address _addr) public pure returns(string) {
    bytes32 value = bytes32(uint256(_addr));
    bytes memory alphabet = "0123456789abcdef";

    bytes memory str = new bytes(51);
    str[0] = "0";
    str[1] = "x";
    for (uint i = 0; i < 20; i++) {
        str[2+i*2] = alphabet[uint(uint8(value[i + 12] >> 4))];
        str[3+i*2] = alphabet[uint(uint8(value[i + 12] & 0x0f))];
    return string(str);

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