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Create and prepare a smart contract

First of all, you need to create and prepare your smart contract to work with it. To do this:

  1. Install Solidity compiler by running the following command:

    npm install -g solc

    You can find the Solidity compiler description and usage here.

  2. Ensure you are in dcloud_example directory, you've created on step 1 here, or create this directory, if you haven't done it yet.

  3. Open a smart contract file greeter.sol, which contains the following code:

    //SPDX-License-Identifier: Unlicense
    pragma solidity ^0.8.13;
    contract Greeter {
    string private greeting;

    constructor() {
    greeting = 'Hello World!';

    function greet() public view returns (string memory) {
    return greeting;

    function setGreeting(string memory _greeting) public {
    greeting = _greeting;

    The main actions in this code example:

    1. Declaration of a new contract variable, where the greeting variable will be stored:

      string private greeting;
    2. Declaration of contract inner variable, where the greeting variable will be stored:

      constructor() {
      greeting = 'Hello World!';

      When you create a smart contract, the greeting variable is initialized with a classical Hello World! text.

    3. The greet() function returns the current greeting.

    4. The setGreeting() function replaces the current greeting with a new one.

  4. Compile the given code. You will receive an .abi file:

    Run the following commands in the directory, where the greeter.sol file is stored:

    1.   solcjs --bin greeter.sol

      As a result you will get a greeter_sol_Greeter.bin file.

    2. You can also find greeter_sol_Greeter.json that you will need in further steps.