pragma solidity ^0.5.9; contract BlockchainTraining { address public organiser; mapping(bytes32 => bool) private participants; constructor() public { organiser = msg.sender; } function addParticipant(string memory name) public { require(bytes(name).length > 0); require(msg.sender == organiser); participants[sha256(abi.encodePacked(name))] = true; } function verify(string memory name) public view returns (bool) { require(bytes(name).length > 0); return (participants[sha256(abi.encodePacked(name))]); } }
0.5.9