Todo CLI

A command-line todo application written in modern C++ using CMake.

This project was built as a practical exercise in C++ software design, focusing on object-oriented programming, separation of concerns, STL containers, file I/O, persistence, JSON serialization, and CMake-based project organization.

Features

• Add tasks
• List tasks
• Mark tasks as completed
• Remove tasks
• Automatic task ID generation
• Persistent task storage
• JSON-based data storage
• Interactive command-line menu
• Input validation

Project Structure

todo-cli/
├── CMakeLists.txt
├── include/
│   ├── nlohmann/
│   │   └── ...                 # nlohmann/json headers
│   └── todo/
│       ├── FileStorage.h
│       ├── Task.h
│       └── TodoManager.h
├── src/
│   ├── FileStorage.cpp
│   ├── Task.cpp
│   ├── TodoManager.cpp
│   └── main.cpp
└── build/

Architecture

The project separates responsibilities between the main components:

Task

Represents an individual todo item.

A task contains:

• ID
• Title
• Completion status

TodoManager

Responsible for todo-related business logic, including:

• Adding tasks
• Removing tasks
• Completing tasks
• Managing the collection of tasks

FileStorage

Responsible for persistence.

It handles:

• Saving tasks to disk
• Loading tasks from disk
• JSON serialization and deserialization
• File I/O

The application uses std::fstream for file operations and nlohmann/json for JSON serialization.

Data Persistence

Tasks are stored in:

tasks.json

Example:

[
    {
        "id": 1,
        "title": "Learn C++",
        "completed": false
    },
    {
        "id": 2,
        "title": "Build Todo CLI",
        "completed": true
    }
]

The persistence flow is:

Save:

std::vector<Task>
       ↓
JSON objects
       ↓
JSON array
       ↓
tasks.json


Load:

tasks.json
       ↓
JSON
       ↓
Task objects
       ↓
std::vector<Task>

Technologies

• C++20
• CMake
• Ninja
• nlohmann/json
• STL
• std::ifstream
• std::ofstream

Building

Configure

From the project root:

cmake -S . -B build -G Ninja

Build

cmake --build build

Run

On Windows:

.\build\todo-cli.exe

Example

===== Todo CLI =====
1. Add task
2. List tasks
3. Complete task
4. Remove task
5. Exit

Choose an option:

Tasks are automatically saved to tasks.json, allowing them to persist between program executions.

Learning Goals

This project was built to practice:

• Modern C++ fundamentals
• Classes and object-oriented design
• Header/source separation
• Encapsulation
• References and const correctness
• STL containers
• C++ file I/O
• JSON serialization and deserialization
• Error handling
• CMake project configuration
• Separation of responsibilities
• Basic persistence architecture

Future Improvements

Possible future improvements include:

• Automated unit tests
• More robust JSON validation
• Better error handling and recovery
• Command-line arguments
• Task priorities and due dates
• Filtering and searching
• Improved project architecture

License

This project is for educational and portfolio purposes.