Banu Prasath Sivakumar

CODE:

#include <iostream>
#include <vector>
#include <cstring>
#include <cstdlib>
#include <ctime>

//Transaction Structure
struct Transaction {
    std::string Sender;
    std::string Receiver;
    double Amount;

    Transaction(const std::string& Sender, const std::string& Receiver, double Amount) : Sender(Sender), Receiver(Receiver), Amount(Amount) {}
};

//Block Structure
struct Block {
    std::string hash; //Current Block,
    std::string previousHash; //Previous Block.
    std::vector<Transaction> transactions;//Vector of Transactions.
    
        Block(const std::vector<Transaction>& transactions, const std::string& previousHash) : transactions(transactions), previousHash(previousHash) {
        hash = generateRandomHash();//Random Hash for Current Block.
    }

    std::string generateRandomHash() {
        const std::string characters = "0123456789ABCDEF";
        const int length = 13;
        std::string hash;
        for (int i = 0; i < length; ++i) {
            int index = std::rand() % characters.length();
            hash += characters[index];
        }
        return hash;
    }
};

// Blockchain class
class Blockchain {
private:
    std::vector<Block> chain;

public:
    Blockchain() {
        std::vector<Transaction> genesisTransactions;//Genesis Block
        Block genesisBlock(genesisTransactions, "0");
        chain.push_back(genesisBlock);
    }

    void addBlock(const std::vector<Transaction>& transactions) {
        const std::string& previousHash = chain.back().hash;
        Block newBlock(transactions, previousHash);
        chain.push_back(newBlock);
    }

    bool validateChain() {
        for (size_t i = 1; i < chain.size(); ++i) {
            const std::string& previousHash = chain[i - 1].hash;
            if (previousHash != chain[i].previousHash) {
                return false;
            }
        }
        return true;
    }

    void printChain() {
        for (const Block& block : chain) {
            std::cout << "Block Hash: " << block.hash << std::endl;
            std::cout << "Previous Hash: " << block.previousHash << std::endl;
            std::cout << "Transactions: " << std::endl;
            for (const Transaction& transaction : block.transactions) {
                std::cout << "Sender: " << transaction.Sender << ", ";
                std::cout << "Receiver: " << transaction.Receiver << ", ";
                std::cout << "Amount: " << transaction.Amount << std::endl;
            }
            std::cout << "--------------------------" << std::endl;
        }
    }
};

int main() {
    std::srand(static_cast<unsigned int>(std::time(nullptr))); // Random number generator.

    // Create blockchain
    Blockchain blockchain;

    // Add some transactions
    std::vector<Transaction> transactions1 = {
        {"Banu", "Prasath", 10000.0},
        {"Prasath", "Sivakumar", 8000.0},
        {"Sivakumar", "Banu", 9000.0}
    };
    blockchain.addBlock(transactions1);

    std::vector<Transaction> transactions2 = {
        {"Radha", "Logesh", 3000.0},
        {"Logesh", "Parvatha", 1000.0},
        {"Parvatha", "Banu", 5000.0}
    };
    blockchain.addBlock(transactions2);
    
    std::vector<Transaction> transactions3 = {
        {"Raja", "Whisley", 800.0},
        {"Whisley", "Nirmal", 500.0},
        {"Nirmal", "Sathish", 900.0}
    };
    blockchain.addBlock(transactions3);

    // Print the blockchain
    blockchain.printChain();

    // Validate the blockchain
    bool isValid = blockchain.validateChain();
    std::cout << "Is Valid: " << (isValid ? "Yes" : "No") << std::endl;

    return 0;
}

OUTPUT:

/tmp/w0VR9Wl4Ea.o
Block Hash: CFBE079BD5233
Previous Hash: 0
Transactions: 
--------------------------
Block Hash: 0F7480C7A5549
Previous Hash: CFBE079BD5233
Transactions: 
Sender: Banu, Receiver: Prasath, Amount: 10000
Sender: Prasath, Receiver: Sivakumar, Amount: 8000
Sender: Sivakumar, Receiver: Banu, Amount: 9000
--------------------------
Block Hash: D5321F1CD236D
Previous Hash: 0F7480C7A5549
Transactions: 
Sender: Radha, Receiver: Logesh, Amount: 3000
Sender: Logesh, Receiver: Parvatha, Amount: 1000
Sender: Parvatha, Receiver: Banu, Amount: 5000
--------------------------
Block Hash: 0BF3E0354B512
Previous Hash: D5321F1CD236D
Transactions: 
Sender: Raja, Receiver: Whisley, Amount: 800
Sender: Whisley, Receiver: Nirmal, Amount: 500
Sender: Nirmal, Receiver: Sathish, Amount: 900
--------------------------
Is Valid: Yes