#include <iostream>
#include <string>
#include <ctime>
#include <vector>

class Transaction {
public:
    std::string sender;
    std::string receiver;
    double amount;

    Transaction(const std::string& s, const std::string& r, double a) : sender(s), receiver(r), amount(a) {}
};

class Block {
public:
    int index;
    std::vector<Transaction> transactions;
    std::string previousHash;
    std::string hash;
    time_t timestamp;

    Block(int idx, const std::string& prevHash) : index(idx), previousHash(prevHash) {
        timestamp = time(nullptr);
        hash = calculateHash();
    }

    std::string calculateHash() {
        // Calculate hash based on index, transactions, previousHash, timestamp, etc.
        // For simplicity, we will use a simple hash function here
        return std::to_string(index) + previousHash + std::to_string(timestamp);
    }

    void addTransaction(const Transaction& transaction) {
        transactions.push_back(transaction);
    }
};

#include <vector>

class Blockchain {
public:
    std::vector<Block> chain;

    Blockchain() {
        chain.emplace_back(Block(0, "0"));
    }

    Block getLastBlock() {
        return chain.back();
    }

    void addBlock() {
        Block newBlock(chain.size(), getLastBlock().hash);
        chain.push_back(newBlock);
    }

    void addTransactionToLastBlock(const Transaction& transaction) {
        chain.back().addTransaction(transaction);
    }
};

int main() {
    Blockchain blockchain;

    Transaction transaction1("Alice", "Bob", 10.0);
    Transaction transaction2("Bob", "Charlie", 5.0);

    blockchain.addTransactionToLastBlock(transaction1);
    blockchain.addTransactionToLastBlock(transaction2);

    blockchain.addBlock();

    for (const Block& block : blockchain.chain) {
        std::cout << "Block " << block.index << " - Hash: " << block.hash << std::endl;
        for (const Transaction& transaction : block.transactions) {
            std::cout << "   Transaction: " << transaction.sender << " -> " << transaction.receiver << " : " << transaction.amount << std::endl;
        }
    }

    return 0;
}