Building a smart contract with Solidity: A Step-by-Step Guide

Imagine you’re in a world where you can make deals with people without worrying about them backing out, messing up, or forgetting their part. That’s what smart contracts on the blockchain do - they’re like super trustworthy digital handshakes. One cool thing you can do with them is create a voting system. In this blog post, I’m going to show you how to build one using Solidity, which is like the ‘French’ of Ethereum smart contracts. Let’s get started!

The Basics

Our voting system will be designed with two main entities: Voter and Candidate. Each entity has its own struct with relevant properties. For instance, a Voter has properties like voterId, voterName, voterImage, voterAddress, voterAllowed, voterVoted, voterVote, and voterIpfs. Similarly, a Candidate has properties like candidateId, age, name, image, voteCount, _address, and ipfs. These properties capture all the necessary details for the voting system.

The Contract

The contract maintains a list of all voters and candidates. It also keeps track of voters who have already voted. This is done using dynamic arrays and mappings. The contract flow begins with the votingOrganizer (the one who deploys the contract) setting up candidates using the setCandidate function and granting voting rights to voters using the voterRight function.

//structure of candidate 
struct Candidate {
        uint256 candidateId;
        string age;
        string name;
        string image;
        uint voteCount;
        address _address;
        string ipfs;
    }
//structure of voter 
struct Voter {
        uint256 voterId;
        string voterName;
        string voterImage;
        address voterAddress;
        uint256 voterAllowed;
        bool voterVoted;
        uint256 voterVote;
        string voterIpfs;
    }

The Functions

The setCandidate function allows the votingOrganizer to create a new candidate. The getCandidates, getCandidateLength, and getCandidateData functions are used to retrieve the addresses of all candidates, the number of candidates, and the data of a candidate given their address, respectively.

The voterRight function allows the votingOrganizer to create a new voter. The vote function allows a voter to vote for a candidate. The getVoterLength, getVoterData, getVotedVoterList, and getVoterList functions are used to retrieve the number of voters, the data of a voter given their address, the addresses of all voters who have voted, and the addresses of all voters, respectively.

Conclusion

Smart contract using Solidity offers a profound insight into the capabilities and possibilities of blockchain technology and smart contracts. This introductory guide aims to elucidate the process, and I hope it has served its purpose effectively. Stay tuned for a comprehensive implementation using Next.js, which will be coming soon. If the world of web3 and blockchain piques your interest, don’t hesitate to reach out and engage in the conversation! 😊