Compile & Deploy
This section covers writing a custom smart contract and deploying it on Harmony Testnet.

Writing our first Counter Smart Contract

In the contracts folder create a new file Counter.sol and add the following code block to it:
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pragma solidity >=0.4.22 <0.8.0;
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​
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contract Counter {
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uint256 private count = 0;
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uint256 moneyStored = 0;
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​
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function incrementCounter() public {
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count += 1;
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}
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function decrementCounter() public {
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count -= 1;
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}
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​
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function addMoney() payable public {
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moneyStored += msg.value;
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}
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​
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function getCount() public view returns (uint256) {
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return count;
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}
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​
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function getMoneyStored() public view returns (uint256){
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return moneyStored;
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}
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}
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​
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In the migrations folder create another new file called 2_Counter.js and add the following code block:
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const Migrations = artifacts.require("Counter");
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​
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module.exports = function (deployer) {
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deployer.deploy(Migrations);
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};
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Checking the Solidity Smart Contract

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truffle compile
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If all was done correctly you should see something like this:
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Compiling your contracts...
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===========================
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> Compiling ./contracts/Counter.sol
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> Compiling ./contracts/Migrations.sol
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> Compilation warnings encountered:
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​
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/home/rachit/Projects/demo/contracts/Counter.sol: Warning: SPDX license identifier not provided in source file. Before publishing, consider adding a comment containing "SPDX-License-Identifier: <SPDX-License>" to each source file. Use "SPDX-License-Identifier: UNLICENSED" for non-open-source code. Please see https://spdx.org for more information.
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​
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> Artifacts written to /home/rachit/Projects/demo/build/contracts
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> Compiled successfully using:
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- solc: 0.7.0+commit.9e61f92b.Emscripten.clang
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Deployment

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truffle migrate --network testnet --reset
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Last modified 8mo ago