cpp-blockchain

A lean, modular C++17 blockchain prototype focused on clarity, testability, and education.

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Table of Contents

• About
• Features
• Architecture
• Quickstart
• Usage Examples
• Development
• Contributing
• License

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About

cpp-blockchain is a small, opinionated blockchain prototype written in modern C++ (C++17).
It prioritizes readable code, modular components, and easy experimentation with core concepts like blocks, transactions, chaining, and consensus primitives.

Use it to learn, prototype consensus ideas, or as a foundation for demos and tests.

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Features

• Minimal block and chain implementation with cryptographic hashing.
• Modular components:
  • Block — holds transactions, metadata, and previous hash.
  • Chain — verifies and stores blocks.
  • Miner — (toy) proof-of-work illustrative miner.
  • Network — pluggable mock networking for tests/demos.
• Unit-tested core logic (fixtures + deterministic tests).
• Clean CMake-based build (Ninja generator supported).

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Architecture

A compact, modular layout:

• src/ — implementation (blocks, chain, miner, utils).
• include/ — public headers.
• tests/ — unit and integration tests.
• CMakeLists.txt — build orchestration.

Mermaid overview:

graph TD;
    A[blocks] -->|ijson| B{chain};
    B -->|m| C[wallet];
    B -->|n| D[miner];
    B -->|o| E[network];
    D -->|extra| B;

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Quickstart

Prerequisites:

• CMake >= 3.15 (project built with CMake 3.31 in CI).
• Ninja (recommended).
• A C++17 toolchain (MSVC, clang, or gcc).

Clone and build:

git clone https://github.com/gnatykdm/cpp-blockchain.git
cd cpp-blockchain
cmake -B build -S . -G Ninja -DCMAKE_BUILD_TYPE=Release
ninja -C build

Run tests (if present):

cd cpp-blockchain
cmake -B build -S . -G Ninja -DCMAKE_BUILD_TYPE=Debug
ninja -C build test

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Usage Examples

Run a simple node (example CLI):

./build/node

Create/add a block (pseudo-CLI):

echo "Creating block..."

Inspecting chain (programmatically):

#include "chain.h"

void inspect_chain(const Chain& chain) {
  for (const auto& block : chain.get_blocks()) {
    std::cout << "Block: " << block.get_hash() << std::endl;
  }
}

(See examples/ for runnable snippets.)

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Development

• CMake: prefer out-of-source builds via -B build -S ..
• Generator: Ninja is recommended for fast incremental builds.
• Compiler flags: use -Wall -Wextra -Wpedantic and sanitize in CI for debug builds.
• Formatting: follow a consistent style; run clang-format or your configured formatter.
• Tests: add unit tests under tests/ and integrate with CTest.

Helpful commands:

# Clean build artifacts
ninja -C build clean

# Re-run CMake configuration
cmake -B build -S .

# Build with specific target
ninja -C build <target_name>

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Contributing

Contributions are welcome. Suggested workflow:

1. Fork the repo.
2. Create a feature branch: git checkout -b feat/your-idea.
3. Add tests for new behavior.
4. Open a PR with a clear description and context.

Please follow the existing module boundaries and keep functions small and testable.

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License

This project is released under the MIT License. See LICENSE for details.

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Enjoy exploring blockchain internals. If you'd like, add an example issue or feature request and start a conversation!