Deploying a Contract on Testnet — Kudos board build (step 3/6)

GoalTrack activity: total kudos, per-recipient counts, and an event log.

What to write

1. Counters
   uint256 public totalKudos; and mapping(address => uint256) public kudosCount;.
   Copy

   mapping(address => uint256) public kudosCount;
   uint256 public totalKudos;

   Public counters auto-generate getters and give users visibility.

2. Event
   emit who sent, who received, and the message.
   Copy

   event KudosSent(address indexed from, address indexed to, string message);

   Indexed params make filtering easy in explorers and backends.

3. sendKudos
   write storage, bump counters, emit event.
   Copy

   function sendKudos(address to, string calldata message) external {
       _lastKudos[to] = message;
       kudosCount[to] += 1;
       totalKudos += 1;
       emit KudosSent(msg.sender, to, message);
   }

   One function does all state changes and logging—easy to test.

Why Events make the app observable off-chain; counters quantify activity.

Try it Deploy, call sendKudos(); watch the event and the counters change.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

contract KudosBoard {
    mapping(address => string) private _lastKudos;
    mapping(address => uint256) public kudosCount;
    uint256 public totalKudos;

    event KudosSent(address indexed from, address indexed to, string message);

    function sendKudos(address to, string calldata message) external {
        _lastKudos[to] = message;
        kudosCount[to] += 1;
        totalKudos += 1;
        emit KudosSent(msg.sender, to, message);
    }

    function lastKudos(address user) external view returns (string memory) {
        return _lastKudos[user];
    }
}

NextWe’ll keep extending this in the following lesson; this version already deploys and runs.