my-first-experiences-with-solidity-smart-contracts-4.sol

event AddressNameChanged(address changer, string previousValue, string newValue);

/// @notice Changes the name for the sender's address
/// @param newName The new name for the sender's address
function changeAddressName(
    string newName
) public {
    emit AddressNameChanged(msg.sender, addressNames[msg.sender], newName);
    addressNames[msg.sender] = newName;
}