What are the best Solidity smart contract examples?

The growth of blockchain technology has brought many important developments to the spotlight. Cryptocurrencies have made their presence felt in financial markets around the world, and blockchain technology has been making headlines everywhere. Is blockchain limited to cryptocurrencies only? No, various blockchain platforms were developing unique and innovative products.

All smart contract code examples will help you understand how smart contract functionality has permanently changed the blockchain landscape. Developers can leverage smart contracts to create complex applications that follow a decentralized approach. Solidity is one of the most widely used programming languages ​​for creating smart contracts, especially for Ethereum. Interestingly, Solidity ensures that smart contract functionality is universally available. Let’s learn about various examples of Solidity smart contract code and their importance.

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Why should I learn examples of Solidity smart contracts?

You may be wondering why you should learn examples of smart contracts in Solidity. The best reason to learn the Solidity smart contract example is the power that Ethereum has on the blockchain industry. Ethereum was the first blockchain to introduce smart contract programming capabilities with the help of Solidity.

Programming smart contracts on Ethereum was not as easy as it is now because only a few programmers were proficient in the EVM architecture. Solidity has emerged as a promising solution to help developers build decentralized applications. The first version of Solidity was released in 2021 and has served as a major driving force in transforming the smart contract development experience for users.

Solidity has helped solve many problems associated with smart contract development, such as compatibility and scalability. The best Solidity smart contract examples can demonstrate how Solidity has reduced the overall difficulty of the smart contract development process. Developing smart contracts using traditional programming languages ​​was a clumsy and complex process.

Solidity served as the next-generation solution to simplify smart contract development. Complexity is removed by linking syntax and structure directly with the EVM. Solidity improves developer convenience by converting written code into EVM code.

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Discover the components of smart contract code in Solidity

The importance of Solidity in smart contract development gives a clear impression of the reasons for its popularity. You might be wondering questions like “How do I write a smart contract in Solidity?” After learning the importance of Solidity. Code in Solidity must be encapsulated in contracts.

A smart contract, or contract in Solidity, contains a collection of code, associated functions, and data or associated state at a specific address on the Ethereum blockchain. Contracts serve as the basic blocks for application development on Ethereum. Below are two examples of Solidity smart contract code that can give you a basic idea of ​​how it works and what Solidity code is made of.

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Basic Solidity smart contract

The best Solidity contract examples to start with are simple ones, like the ‘helloWorld’ example for other programming languages. A simple smart contract in Solidity looks like this:

pragma solidity ^0.5.0;

 
contract firstContract 

 function helloWorld () public pure returns (string) 

   return "HelloWorld !. This is your first Contract";

 

The code example has one method called “helloWorld()”. This method returns “HelloWorld!.” This is the first contract” string that is output.

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Solidity smart contract using set() and get() functions

Another notable addition among the best Solidity smart contract examples are smart contracts that can use set() and get() functions. The following example uses the set() function to set the value of a smart contract’s state variable. On the other hand, the get() function can help you get the value set in the contract.

// SPDX-License-Identifier: GPL-3.0 

pragma solidity >= 0.4.16 < 0.9.0;

contract Storage



       uint public setData;

     function set(uint x) public

    

        setData = x;

    

     function get(

    ) public view returns (uint) 

        return setData;

    

Let’s analyze this smart contract code example to understand how to create a contract using Solidity. Important components to note in the contract code example are:

pragma solidity >=0.4.16 <0.9.0;

Smart contract code begins with a pragma, which serves as instructions for the compiler on how to process the code. All Solidity source code must begin with a ‘version pragma’, which formally declares which version of the Solidity compiler to use. Using the version pragma in this Solidity contract example demonstrates its functionality in all Solidity contract code. This helps avoid compatibility issues with future versions of the compiler that may contain some changes. In this example, you can see that the code is compatible with compiler versions higher than 0.4.16 and lower than 0.9.0.

The ‘contract Storage ‘ component of the code focuses on the contract keyword. This plays an important role in declaring a contract that encapsulates your code.

Another common highlight in answers to “How do I write a smart contract in Solidity?” is the state variable. In this example, you can see the state variable in the following line:

unit public setData;

State variables are permanently added to the contract storage and written directly to the Ethereum blockchain. That line in the code example provides the declaration of the state variable “setData” using type ‘uint’, or an unsigned integer of 256 bits. You can think of this line as a way to add a slot to the database.

The most important highlight in the smart contract code example is the function declaration:

function set(uint x) public

function get() public view returns (uint)

You can see these two functions in different parts of the smart contract code. First of all, there is a ‘set’ function that has a public access modifier type. This function takes as parameter a variable x of data type uint. This can provide essential additional functionality to a simple smart contract for updating the value of “setData”.

This feature allows anyone to call and overwrite the “setData” value stored on the Ethereum blockchain without any barriers. So you have a completely decentralized and censorship-resistant smart contract that is unaffected by centralized server shutdowns.

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What other Solidity contract examples should you learn about?

A simple example of a Solidity contract demonstrates the basics needed to find your way through Solidity contract development. Conversely, you can find the best examples of Solidity smart contracts that meet your new requirements. Examples will not only help you understand the power of Solidity, but will also help you level up your game in Solidity programming. Here are some notable examples of Solidity smart contracts for various purposes:

ERC-20 token contract

The ERC-20 token standard is an essential addition to the checklist of every aspiring Solidity developer. This helps define a specific set of rules for creating fungible tokens. Below is an example of Solidity’s ERC-20 token contract.

contract ERC20Token 
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    uint256 public totalSupply;

    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    constructor(uint256 initialSupply, string memory tokenName, string memory tokenSymbol) 
        totalSupply = initialSupply * 10 ** uint256(decimals);
        balanceOf(msg.sender) = totalSupply;
        name = tokenName;
        symbol = tokenSymbol;
    

    // Additional functions...

ERC-721 Token Contract

Among the best Solidity smart contract examples, the next addition will put the spotlight on ERC-721 tokens. The ERC-721 standard can be used for NFT creation. Below is an example of Solidity’s ERC-721 token contract.

contract ERC721Token 
    string public name;
    string public symbol;

    mapping(uint256 => address) public ownerOf;
    mapping(address => uint256) public balance;
    mapping(uint256 => address) public approved;

    event Transfer(address indexed from, address indexed to, uint256 tokenId);
    event Approval(address indexed owner, address indexed approved, uint256 tokenId);
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    function transferFrom(address from, address to, uint256 tokenId) external;
    function approve(address to, uint256 tokenId) external;
    
    // Additional functions...

general auction contract

You can also create online auctions on the blockchain using Solidity smart contracts. Developers can utilize a simple auction contract for this purpose. Contracts can help bidders compete for items, with the highest bidder winning at the end of the auction. Below is an example of a generic auction contract that can be created in Solidity.

contract SimpleAuction 
    address public beneficiary;
    uint256 public auctionEndTime;

    address public highestBidder;
    uint256 public highestBid;

    mapping(address => uint256) public pendingReturns;

    bool public ended;

    event HighestBidIncreased(address bidder, uint256 amount);
    event AuctionEnded(address winner, uint256 amount);

    constructor(uint256 _biddingTime, address _beneficiary) 
        beneficiary = _beneficiary;
        auctionEndTime = block.timestamp + _biddingTime;
    

    function bid() public payable;
    function withdraw() public returns (bool);
    function auctionEnd() public;
    
    // Additional functions...

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final words

If you review the Solidity smart contract examples, you will see that Solidity is a simple and straightforward programming language. You don’t need to be a programming expert to learn how Solidity works. Moreover, the variety of use cases for Solidity contracts presents a more advantageous way to adopt them.

Solidity will be a key driver of the web3 revolution by supporting NFT and dApp development. You can also start your learning journey and become a Solidity expert as soon as possible. Learn more about the basics of Solidity and how you can get the best results from Solidity right away.

*Disclaimer: This article should not be considered, and is not intended to be, investment advice. The statements made in this article are not investment advice and should not be taken as such. 101 Blockchain is not responsible for any loss suffered by anyone relying on this document. Do your own research!